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DISEASES OF PLANTS 


INDUCED BY CEYPTOGAMIC PAEASITES 



DISEASES OF PLANTS 

Induced by Cryptogamic Parasites 


Introduction to the Study of 
Pathogenic Fungi, Slime -Fungi, Bacteria , & Algae 


BY 

Dr. KARL FREIHERR von TUBEUF 

PRIVATDOZENT IN THE UNIVERSITY OF MUNICH 


(English (Ebition bg 

WILLIAM G. SMITH, B.Sc., Ph.D. 

LECTURER ON PLANT PHYSIOLOGY 
UNIVERSITY OF EDINBURGH 


THREE HUNDRED AND THIRTY ILLUSTRATIONS 


LONGMANS, GREEN & CO. 

LONDON, NEW YORK, AND BOMBAY 


1897 


All rights reserved 


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AUTHOR’S PREFACE. 


In my research work, and in connection with my lectures at 
the University and Technical School of Munich, I have for 
some time felt convinced that there existed a very evident gap 
in the literature relating to the diseases of plants. There was 
need of a newer and more complete work on cryptogamic para- 
sites aud the diseases induced by them on higher plants, a work 
furnished with many accurate illustrations, with a survey of 
the newer literature, and with a general part wherein parasitism 
and the relations between parasite and host are discussed from 
a botanical standpoint. Therefore, I have undertaken to write 
a book intended to supply in some degree this pressing want. 
Here the attempt has been made for the first time to review 
in a general and comparative manner the biological, physiological, 
and anatomical relationships accompanying the phenomena of 
parasitism. Already De Bary has considered the varying degrees 
of parasitism and the phenomena of symbiosis in his celebrated 
Morphology and Biology of the Fungi ; while AVakker has laid 
the foundations of our knowledge of the alterations in the 
anatomy of plants diseased by the agency of fungi, more especially, 
however, those alterations accompanying ‘hypertrophy.’ I venture 
to continue this difficult and comprehensive chapter of plant 
physiology, because for ten years I have devoted my time to 
the study of plant pathology. The book may be all the more 
acceptable since I have confirmed a large number of the 
observations and added the results of my own investigations, 
many of them now published for the first time. 

The present time is favourable to my work. The great 
Sylloge Fungorum of Saccardo (with its appendices in A'ols. ix. 
and x.) has been recently completed ; the classic investigations 


VI 


author’s preface. 


of Brefelcl in the domain of mycology, and containing his 
classification of the fungi, are now well advanced ; the Krypto- 
gctmen-Flora of Rabenhorst is nearly completed ; and the newer 
literature and observations are now periodically reviewed in the 
Zeitschrift fur Pjlanzcnhranlcheiten, and other magazines. The 
recent publication of several investigations on the influence of 
parasites on the anatomy of their host-plants greatly facilitated 
the compilation of the general part of the work. 

I have here attempted to summarize in a systematic manner 
the preventive and combative agencies available against the 
more important diseases of economic plants. In many cases 
these are supported by facts given in the chapters on the 
natural and artificial infection of host-plants, and their disposition 
towards diseases produced by lower organisms. 

As already indicated in the title-page, the book deals only 
with those diseases of plants produced by the cryptogams and 
other lower organisms of the vegetable kingdom. The large 
number of parasites which attack such lower plants as algae 
and lichens, although not altogether neglected, have as a rule 
been omitted, otherwise the book could not have been brought 
within the limits of a single volume. In the second or systematic 
part of the book, the pathological phenomena are considered 
along with the description of the organism producing them. 
A here the diseases are of economic importance, measures for pre- 
vention and extermination are also suggested. Notices of greater 
length are given to such parasites and diseases as have formed 
the subject of special investigations. We could only aim at a 
complete list for Germany and the neighbouring countries, yet 
we have included many species of interest occurring in other 
parts of the world, notably in America. 

I hough it will be possible to identify most of the more 
important parasites by the aid of this book, we do not intend 
it to replace the systematic works ; we purpose rather to add 
to the descriptions given in Rabenhorst, Saccardo, and similar 
works. I his book is intended above all to be, in the terms 
of its title-page, “ an Introduction ” ; hence it seeks to orient 
in a general way, to give a summary of our knowledge, and to 
indicate the way to more detailed records. On this account 
great care has been taken in the citation of home and foreign 
literature, not only up to the time of finishing the manuscript 


author’s preface. 


vii 

(Easter, 1894), but also during the time of proof-reading up 
till the following Christmas. 

Reference to the book will be rendered easier by the numerous 
illustrations, which are almost exclusively the work of the author, 
and reproduced either from drawings or from photographs of the 
living objects, in many cases taken in situ. I consider it more 
essential to illustrate the habitus of pathological objects rather 
than to give drawings of microscopic subjects ; those one may 
find in other works. Some of the illustrations are copied from 
the excellent plates of Tulasne, Woronin, De Bary, Klebs, Reess, 
Cohn, and Robert Hartig ; while a number of woodcuts have 
been borrowed from the well-known Lehrbuch der Baumkrank- 
heiten of the last named author. 

The grouping of the ‘ Fungi imperfecti,’ which have not yet 
been worked up for the German flora, is based on Saccardo’s 
Sylloyc ; hence the arrangement into Hyalosporae, etc., which 
is intended for the benefit of those having access to Saccardo. 
Particular attention has been paid in the two Indices to the 
scientific names of both parasites and hosts, to popular names, 
and to technical expressions. 

In my labours I received great assistance from the following 
sources : From the collection of pathological material begun by 
Professor Robert Hartig, and now carried on with my help in 
the Botanical Institute of the Royal Bavarian School of Forestry 
in Munich ; from the facilities for research and photography 
afforded by the laboratories of the same institution ; from the 
Royal Library of Munich, the Library of the University, and the 
private pathological library of Professor Hartig. 

Living material for investigation has been kindly sent to me 
from many sources, particularly from the following gentlemen : 
Herr Lehrer Schnabl of Munich, Geli. Oberregierungsrath Prof. 
Kuhn of Halle, Hofgartner Kaiser of Munich, Prof. Ur. Fries 
of Upsala, Forstrath von Plonnies and Oberforster Losch at 
Amorbach. Preserved material came from Herr Hauptlehrer 
Allescher of Munich, Director Dr. Goethe and Dr. Wortmann in 
Geisenheim, Prof. Dr. Stahl of Jena, Prof. Dr. Magnus of Berlin, 
Prof. Dr. Grasmann and Prof. Dr. Loew of Tokio. Dr. Bruns 
of Erlangen kindly photographed some specimens in the botanical 
museum there. Numerous botanists have greatly assisted me by 
sending papers, especially Dr. Dietel of Leipzig : I have also to 


author’s preface. 


viii 

thank him for valuable aid with the Uredineae. To Prof. Dr. 
Soxhlet I am indebted for literature and the opportunity given 
to establish a museum of pathological material in connection with 
the agricultural division of the Munich Technical School. I)r. 
Solla of Trieste, while working in our laboratory here, very 
kindly translated the earlier fascicles of the ‘ Funghi parasitici ’ 
of Briosi and Cavara as far as they were then published. Prof. 
Dr. Wollny allowed me to carry out some researches on his 
experimental fields. Very opportune were the investigations of 
my pupils, Dr. 'SVoernle and Dr. W. G. Smith, on the anatomical 
changes in plants attacked by Gymnosporangeae and Exoasceae 
respectively. 

To all these gentlemen, and to many more who sent me 
material, but whom it is impossible to name individually in 
this place, I here express my warmest thanks. 

The reproduction of my drawings and photographs has been 
most carefully carried out by Herr 0. Consi^e of Munich. I am 
also deeply indebted to the publisher, Herr Springer, for the 
excellent manner in which he has done his work ; this will 
no doubt be also appreciated by the reader. 

v. TUBEUF. 

Munich, December, 1894. 


NOTE TO THE ENGLISH EDITION. 

Since the publication of this work, I have received a large 
contribution of original papers. Though there was no time to 
embody all these in the English edition, yet many of them 
have been used for its correction and amplification. Some were 
of such a kind as to necessitate the re-writing of whole sections, 
notably those on the genera Exoascus and Gymnospomngium. 
The remainder will be thoroughly revised if a second German 
edition be called for. I again take the opportunity of thanking 
all those who have sent me literature, and I shall be grateful 
if they will continue to do so in the future. 

v. TUBEUF. 

Munich, December, 1895. 


PREFACE TO THE ENGLISH EDITION. 


My justification for placing another translation in our libraries 
is that no such book as this exists in the English language, 
and that I could not, for some considerable time, see my way 
to collect so many observations on the cryptogamic parasites of 
higher plants, or to find so many suitable subjects for the 
pictorial illustration of their habits and structure, as Dr. von 
Tubeuf has given us. The work was undertaken all the more 
willingly, because, while working under the guidance of the 
author, I had seen the book take shape in his hands, and even 
added some items to its pages. 

The aims of the book are sufficiently set forth in the author’s 
preface, and in the preparation of an English edition these 
have been kept in view. The first or general part and the 
more important descriptions in the second part are practically 
translations, but a certain amount of modification was found 
necessary in adapting the work to the requirements of English 
readers. With this object many additions were made both 
by the author and myself. Those which I have inserted are 
in most cases indicated by the use of (Edit.); this has, how- 
ever, been entirely omitted in the group ‘Fungi imperfecti,’ 
and nearly so in the Uredineae, on account of the number of 
changes found necessary. I also thought it advisable to indicate 
whether the different species of fungi had been recorded for 
Britain and North America ; this has been done generally by 
the use of brackets, — (Britain and U.S. America.) The records 
for Britain are taken from the works of Plowright, Massee, and 
others ; those of three groups, — the Uredineae, Basidiomycetes, 
and ‘ Fungi imperfecti ’ were, however, revised by Professor J. 
W. H. Trail of Aberdeen, a well-known authority. For America 


X 


PREFACE TO THE ENGLISH EDITION. 


the records of economic interest are selected chiefly from Farlow 
and Seymour’s Host-Index, which contains the complete list. 

I here take the opportunity of expressing my thanks to 
Professor I. Bayley Balfour for valuable aid and advice ; to 
Professor J. W. H. Trail for kindly revising important parts of 
the proofs; to my brother, Pobert Smith, for assistance in proof- 
reading, and to other friends who have aided me. 

The difficulties of translation are well known ; in the present 
case they have been increased by the technical nature of the 
subject, and by the modification which the original has under- 
gone. Faults there must be ; for those I ask the indulgence of 
the reader. 

W. G. SMITH. 


Royal Botanic Garden, 

Edinburgh, October, 1896. 


BIBLIOGRAPHY. 


The following are some of the more important general works and text 
books. Books and papers on special subjects are given throughout the 
text as foot-notes : — 


General Works on Fungi. 

Tulasne. Selecta fungorum carpologia. 1861-1865. 

De Bart. Comparative Morphology and Biology of the Fungi, Mycetozoa, 
and Bacteria. English edition. 1887. 

Zopf. “ Die Pilze.” Schenk’s Handbuch der Botanik. 1890. 

Ludwig. Lehrbuch der niederer Kryptogainen. 1892. 

Brefeld. Untersuchungen aus clem Gesammtgebiete der Mycologie. 
1872-1891. 

Tavel. Vergleichende Morphologie der Pilze. 1892. 

Saccardo. Sylloge fungorum. 1882-1893. 

Winter, Fischer, and Behh. “ Die Pilze.” Rabenhorst’s Kryptogamen- 
flora. 

Schroeter. “ Die Pilze.” Cohn’s Kryptogamenflora von Schlesien. 1885- 
1894. (Incomplete.) 

Schroeter. “ Die Sclileimpilze und die Pilze.” Engler-Prantl natiirlichen 
Pflanzenfamilien. 1892-1894. (Not yet complete.) 

Cooke. Handbook of British Fungi. 1871. 

Plowright. British Ustilagineae and Uredineae. 1889. 

Farlow and Seymour. Host-Index of the Fungi of the United States. 
1888-1891. 

Massee. British Fungus-Flora. 1892-1895. 


Works on Diseases of Plants. 

Unger. Die Exantheme der Pflanzen und einige mit diesen verwandte 
Krankheiten der Gewaclise. 1833. 

Wiegmann. Die Krankheiten und krankhaften Misbildungen der Gewaclise. 
1839. 

Meten. Pflanzenpathologie. 1841. 


BIBLIOGRAPHY. 


xii 

De Bary. Untersuch ungen iiber die Brandpilze und die durch sie verur- 
sachten Krankheiten der Pflanzen. 1853. 

Kuhn. Die Krankheiten der Kulturgewiichse und ihre Yerhiitung. 1858. 

Hallier. Phytopathologie ; die Krankheiten der Kidturgewiichse. 1868. 

Hartig, R. Wichtige Kranklieiten der Waldbaume. 1874. 

Hartig, R. Die Zersetzungserscheinungen des Holzes. 1878. 

Frank. Die Krankheiten der Pflanzen. I. Aufl. 1880, II. Aufl. 1894-1896. 

Hartig, R. Lehrbuch der Baumkrankheiten. I. Aufl. 1882, II. Aufl. 1889. 
(Editions in English, French, and Russian.) 

Smith, Worth. G. Diseases of Field and Garden Crops. 1884. 

Soracer. Handbuch der Pflanzenkrankheiten. II. Aufl. 1886. 

Wolf and Zopf. Krankheiten der landwirthschaftlichen Nutzpflanzen 
durch Schmarotzerpflanzen. 1887. 

Sorauer. Die Schaden der einheimischen Kulturpflanzen durch thierische 
und pflanzliche Schmarotzer. 1888. 

Marshall Ward. Timber and some of its Diseases. 1889. 

Kirchner. Die Krankheiten und Beschiidigungen unserer landwirthschaft- 
lichen Kulturpflanzen. 1890. 

Frank and Sorauer. Pflanzenschutz. 1892. 

Prilliecx. Maladies des plantes agricoles et des arbres fruitiers et forestiers 
causees par des parasites vegetaux. 1895. 

Zeitschrift fiir Pflanzenkrankheiten (since 1891). 

The Publications of the Division of Vegetable Pathology of the Department 
of Agriculture, U.S. America, issued from Washington. 

The Bulletins of the Agricultural Experimental Stations, issued by many of 
the States and Universities of the United States. 

Exsiccata of Parasitic Fungi, by (a) Briosi and Cavara, (5) Eriksson. 

“Economic Fungi” of U.S. America, by Seymour and Earle; Exsiccata 
begun 1890, (still being issued). 

Etc., etc. 


CONTENTS. 


PART FIRST. 

CHAPTER I. 

THE PARASITIC FUNGI. 

PAGE 

1. Definition of the Parasitism of Fungi, - - - 2 

2. Classification of Parasites and Saprophytes, - - 3 

3. Mode of Life of the Parasitic Fungi, - - - 7 

CHAPTER II. 

REACTION OF HOST TO PARASITIC ATTACK. 

4. Effect of Parasitic Fungi on their Host, - - - 14 

5. Effect of Parasitic Fungi on the Form of the Host-Plant, 22 

6. Effect of Parasitic Fungi on Cell-Contents, - - 31 

7. Effect of Parasitic Fungi on the Cell-Wall, - - 36 

8. Effect of Parasitic Fungi on the Tissues of their Host, 40 

CHAPTER III. 

RELATION OF PARASITE TO SUBSTRATUM. 

9. Effect of the Substratum on the Development of the 

Parasite, ------- 45 


XIV 


CONTENTS. 


CHAPTER IV. 


§ 10. NATURAL AND ARTIFICIAL INFECTION, - - 50 

CHAPTER V. 

§ 11. DISPOSITION OF PLANTS TO DISEASE, - - 58 

CHAPTER VI. 

§ 12. PREVENTIVE AND COMBATIVE MEASURES, - - 63 

I. Extermination and Removal of the Parasitic 

Fungi alone, - - - - - 65 

II. Removal and Destruction of Diseased Plants, - 71 

III. Avoidance or Removal of Conditions which Favour 

Infection, ------ 75 

IV. Selection of Hardy Varieties, - - - 81 


CHAPTER VII. 


§ 13. ECONOMIC IMPORTANCE OF DISEASES OF PLANTS, 83 


CHAPTER VIII. 


SYMBIOSIS: MUTUALISM, 


86 


CHAPTER IX. 

SYMBIOSIS: NUTRICISM, - 

Ectotrophic Mycorhiza, 

Endotropiiic Mycorhiza, 

Mycodomatia of the Alder, etc., 
Mycodomatia of the Leguminosae, 


92 


93 


97 


9!) 


101 


CONTENTS. 


XV 


PART SECOND. 

SYSTEMATIC ARRANGEMENT OF THE CRYPTOGAMIC 
PARASITES. 

PAGE 

I. THE PATHOGENIC FUNGI OF PLANTS, - - 104 

A. Lower Fungi (Phycomtcetes), - - - 106 

(1) Chytridiaceae, ..... 106 

(2) Zygomycetes, - - - - - - 114 

(3) Oomycetes : Peronosporeae, .... 115 

B. Higher Fungi (Mycomycetes), .... 135 

Ascomycetes, - - - - - - 136 

A . Gymxoasci, ..... 137 

The Parasitic Exoasceae, - - - 144 

B . Carpoasci, - - - - - - 168 

Perisporiaceae, .... 170 

Pyrenomycetes, - - - 183 

Hysteriaceae, ----- 232 

Discomycetes, ----- 240 

USTILAGINEAE, - - - - - 275 

Uredineae,- ------ 328 

Basidiomycetes, ------ 421 

Fungi Imperfecti— I. Sphaeropsideae, - - - 463 

II. Melanconieae, - - - 482 

III. Hyphomycetes, - - - 496 

II. THE PATHOGENIC SLIME-FUNGI, - - 522 

III. THE PATHOGENIC BACTERIA, - - - - 530 

IV. THE PATHOGENIC ALGAE, - - - 539 

INDEX OF PARASITES, ------ 556 

GENERAL INDEX, 580 


ERRATA. 


Page 


9, Fig. 1, for “ Erysipheae ” read “ Erysiphe.” 

35, line 11 from foot, for “ tyrosin ” read “ trypsin,” 

181, ,, 24, /or “ quercinium ” read “ quercinum.” 

185, ,, 6, /or “ Nectrina ” read “ Nectria,” 

195, ,, 3, /or “ setuloso ” read “ setulosa«” 

256, ,, 6, for “ Belionella ” read “ Beloniella,” 

305, ,, 11 from foot, /or Tolysporium” read “Tolyposporium.” 

312, ,, 16, /or “ heloscladii ” and “ Heloscladium ” respectively, 
read “ helosciadii ” and “ Helosciadium.” 

337, „ 10, for “ Onybrychis ” read “ Onobrychis.” 

355, ,, 25, for “ Cichoria ” read “ Cichorium,” 

403, ,, 9, /or “ Cypressus ” read “ Cupressus.” 

404, ,, 5, for “ Escheveria ” read “ Echeveria.” 

420, ,, 3, for “ Thecospora ” read “ Thecopsora.” 


PART FIRST. 


CHAPTER I. 

THE PARASITIC FUNGI. 

The true Fungi, together with the Myxomycetes or Slime-fungi, 
and the Schizomycetes or Bacteria, constitute a group of the 
Cryptogams characterized by lack of chlorophyll. In consequence, 
the members of the group are unable to utilize light as a source 
of energy, and must obtain their food as organized material, 
complex in comparison with the simple substances required by 
green plants. These fungi, in short, are, in common with animals, 
ultimately dependent for the greater portion of their support 
on living or dead chlorophyllous plants. According as they 
obtain nutriment from dead organic remains or from living 
plants or animals, we distinguish them as Saprophytes and 
Parasites respectively. The same mode of nutrition is found 
in the case of most non-chlorophyllous Phanerogams, and also 
in a few chlorophyllous plants, both Cryptogams and Phanero- 
gams. 

When parasitic Fungi, Bacteria, and other lower organisms 
attack higher plants, they, as a rule, endeavour to penetrate the 
living organs of their host. It is only when this penetration 
has taken place to some extent, and the parasite has thereby 
come into more or less close contact with the tissues of its host, 
that conditions suitable to a parasitic mode of nutrition are 
established. 

To deal with the lower forms of vegetable parasites, with their 
relations to their respective hosts, and with the structural altera- 
tions which they bring into existence in the latter, is our object 
in the present book. 

A 


2 


THE PARASITIC FUNGI. 


§ 1. DEFINITION OF THE PARASITISM OF FUNGI. 

Parasitic Fungi are those which, stimulated by the cell- 
contents of another living plant, penetrate wholly or partially 
into its tissues, and draw their nutriment from that source. 

Saprophytic Fungi are those which make no attempt to 
penetrate the tissues of living plants, but derive their nutriment 
from a dead substratum. 

Intermediate between these two extremes come those fungi 
which, in consequence of some stimulus, attempt to effect an 
entrance into the tissues of living plants by the secretion of some 
fluid or ferment, but only attain their object after first killing the 
part they attack (e.g. Sclerotinia sclerotiorum). A special position 
must also be ascribed to certain forms which inhabit the wood 
of trees, but have not the power to penetrate through the outer 
tissues ; they depend on first gaining entrance through wounds 
into dead parts of the bark or wood, and, after living there for 
a time as saprophytes, extend into the living elements and cause 
their death. 

Many parasites may be artificially cultivated so as to pass 
some part of their life-history on dead pabulum, and even in 
natural conditions many of them regularly live for a season in 
a saprophytic manner. On this account it appears to me more 
correct, in distinguishing between parasites and saprophytes, to 
lay less weight on the adaptation to nutrition and more on their 
response to the stimuli exerted by living plant-cells. The nature 
of this stimulus which affects parasitic hyphae has not as yet 
been investigated. It appears probable, however, especially from 
the investigations of l’feffer and Miyoshi, 1 that the influence is 
primarily a chemical one, and that the nutritive value of the 
stimulating substance is not a measure of the ensuing effect. 
Biisgen states that the formation of adhesive-discs by germinating 
spores is induced by a stimulus due to contact, whereas the 
production and penetration of the first haustorium is independent 
of contact, and is probably due to some chemical stimulus (see 
p. 9). Miyoshi’s investigations have also proved that saprophytic 
fungi are capable of penetrating into living plant-organs, even 

1 Miyoshi. “ Ueber Chemotropismus cl. l’il/.e." Botan. Ztitung, 1894: also “ Die 
Durchbohrung von Membranen (lurch Pilzfailen.’’ Primjxheim's Jahrhuch, 1 Silo 

Pfeffer. “ Ueber Election orintnischer Nahrstoffe." 1'riminlitim' * Juhrbuch, 
1895. 


DEFINITION OF THE PARASITISM OF FUNGI. 


3 


of boring through cell-walls, if the part be impregnated with a 
stimulating solution. They behave here completely as parasites. 
For example, hyphae of Penicillium glaucum penetrate into living 
cells of a leaf injected with a two per cent, solution of cane 
sugar, while without previous injection of the leaf they have 
never been observed to do so. Penicillium is also known, in 
certain circumstances, to become parasitic. 

Many species of fungi are capable of passing the whole or a 
part of their life as parasites on living plants. Conspicuous in 
this respect are the Uredineae and Ustilagineae, many Ascomy- 
cetes, including all Exoasceae and Erysipheae ; and amongst the 
lower fungi, most of the Chytridiaceae and all the Peronosporeae. 
Xor does this exhaust the list, for amongst the remaining fungi 
we may find isolated families, genera, and even species occurring 
as parasites, while forms closely related to them are saprophytic. 

To classify the parasites, saprophytes, and intermediate forms, 
we shall adopt that arrangement proposed by Van Tieghem and 
De Bary. 

§ 2. CLASSIFICATION OF PARASITES AND SAPROPHYTES. 

1. True saprophytes are such as regularly pass through their 
whole life-history in a saprophytic manner. They may derive 
their nourishment from different kinds of pabulum, or be limited 
to some definite substratum. The true saprophytes do not come 
within the scope of this book. 1 

2. Hemi-saprophytes (the ‘facultative parasites’ of De Bary) 
ai’e wont to pass through their whole development as saprophytes, 
but on occasion are capable of existing wholly or partially as 
parasites. Amongst them are included particularly such species 
as may be designated “ occasional parasites,” which commonly 
occur as saprophytes, and only under certain conditions become 
parasitic. 

3. True parasites (the ‘obligate parasites’ of De Bary). These 
undergo no part of their development as saprophytes, but live in 
every stage of existence as parasites. 

•f. Hemi-parasites (the ‘facultative saprophytes’ of De Bary) 
are capable, if need be, of becoming saprophytes for a season 

1 Johow proposes the term Holo -saprophytes for those uon-chlorophyllous 
Phanerogams which live exclusively saprophytic on organic debris, in contrast 
to those possessing chlorophyll, which he names Hemi-saprophytes. 


4 


THE PARASITIC FUNGI. 


but as a rule they live throughout their whole development as 
parasites. 

Within each of these four divisions one may introduce a 
number of subdivisions. 


Hemi-saprophytes. 

The majority of saprophytes are never parasitic, yet there are 
a number which become so occasionally. Thus some species of 
Macor and Penicillium can penetrate into thin-skinned fruits, and 
this they do the more easily, the further the fruits are from the 
condition of full vital energy, to use I)e Bary’s expression . 1 
Belated to these are other fungi which, although incapable of 
effecting entrance into plants in active life, may yet do so as 
the plant, though still living, begins to wither. In such cases 
the parasitism is somewhat difficult to prove. In particular, the 
so-called ‘ Fungi imperfecti ’ contain forms of this kind. 

Amongst the hemi-saprophytes we may include the species 
of Botrytis, which are able to penetrate into unfolding parts of 
plants, but not into the older parts. We may specially mention 
Botrytis Douglasii as a form more generally known as a sapro- 
phyte, but which becomes parasitic on immature organs, and 
which penetrates young needles of various conifers to kill them, 
whereas it is unable to attack older needles. In this case the 
thickness of the membranes would seem to act as a protection, 
just as the vital energy of the plant does in the preceding cases. 
In Sclerotinia sclerotiorum, Scl. ciborioides, and Set. Fucl'cliana , 
a saprophytic existence must, as in the example just mentioned, 
precede the parasitic condition; in fact De Bary holds that 
these forms can only become parasites after their mycelium has 
been saprophytically strengthened ; tin* parasitic condition is not 
necessary to them, for they can go through their whole develop- 
ment on a dead substratum. Pythium Dc Baryanum is also to- 
be regarded as a liemi-saprophyte which attacks and kills 
seedlings of many plants as a parasite, but otherwise vegetates 
on dead plant remains. Cladosporium, herbartnn , one of the 
commonest of saprophytes, behaves similarly, but it is of less 
frequent occurrence than Pythium, and in fact its parasitism has 
only been suspected quite recently. 

'This lias been confirmed bv Davaine (Compt. rend, lxiii., IStUi, ]>|>. 277 and 
344) and Brefeld (Sitznn<j*btr. d. naturforneh. Fr. :n Berlin, 1875). 


CLASSIFICATION OF PARASITES AND SAPROPHYTES. 


5 


As further examples of fungi, capable, as parasites, of killing 
living cells, but which pass through more or less of their life 
as saprophytes, may be taken species whose mycelium inhabits 
the wood of trees and shrubs. Amongst these are numerous 
Polyporeae, which find admission only by wounds in the wood. 
At first these destroy and derive nourishment from the substance 
of dead parts of the wood, but later they begin to attack the 
parenchyma of the living wood, and extending outwards kill, 
as they go, cambium, bast, and rind, till they reach the exterior, 
and there develop sporophores. As examples we may take 
those species investigated by E. Hartig of Munich, eg. Poly- 
porus fomentarius, P. igniarius, P. Hartigii, P. sulphur eus, 
Stereum hirsutum, Trarnctes pini} 

The heart-wood is a part of the tree generally avoided by 
insects, which would in very short time destroy the sap-wood 
with its rich starch-content, c.g. Annobiae in oak. Again, the 
heart-wood resists the influence of certain saprophytic fungi 
much longer than the sap-wood, hence it is preferred as the 
timber used for railway sleepers. Although in these cases we 
might describe the heart-wood as possessing antiseptic properties, 
yet this would scarcely be accurate, since it is just this very 
heart-wood which is always first attacked by the wound-parasites 
of trees, and gives them a hold on the tree as parasites. See 
also Chap. V. 

Since these dangerous tree-fungi can live wholly as sapro- 
phytes in the heart- wood, and in the sap-wood partly as such, 
partly as parasites, they are also able to vegetate further, and 
to reproduce themselves on felled stems, especially when the 
necessary moisture is provided. Thus, for example, Agaricus 
adiposus, a wound-parasite of the silver fir, produces its yellow 
sporophores on felled stems and split wood during the whole 
summer in moist parts of the forest, while in a cellar or other 
moist chamber the development of sporophores may continue over 
a year. In fact, I have found that a billet of beech-wood, after 
being placed under a glass and allowed to lie completely dry, 
on again being soaked from time to time, continued to produce 
a crop of toadstools annually for five years. 

Some wound-parasites occur occasionally as typical sapro- 
phytes on dead wood. Thus Polyporvs annosus, perhaps better 

1 R. Hartig, Zersetzungserscheinungen des Holzes, 1878, ami other works. 


G 


THE PARASITIC FUNGI. 


known as Trametes radiciperda, is an undoubted parasite of 
pines, spruces, and other trees, yet on timber in mines 1 it 
grows luxuriantly, and reproduces abundantly from sporophores, 
which, however, differ somewhat from the typical form. Again, 
the rhizomorph-strands of Agaricus melleus grow under dead 
bark, in the earth, in mines, and in wooden water-pipes, while 
other forms of its mycelium are completely parasitic ; thus 
the apices of the rhizomorphs penetrate the bark of young 
conifers, and, in the form of a mycelium, live parasitic on rind, 
bast, and cambium. 

Polyporus vapovarius, a true parasite on living Scots pine, 
is also an enemy of timber in newly-built structures, or in 
subterranean spaces and cellars, so long as it can obtain the 
necessary moisture. Polyporus sulphureus produces sporophores 
on the bark of living trees, as well as on the dead stools of 
felled trees. Many other related forms would probably be able 
to live on dead timber if they were not dependent on a certain 
degree of moisture, and could submit to drying-up as easily as, 
for example, Polyporus abietinus, a true saprophyte, and one of 
the most common enemies of old wooden bridges. 

Fungi from other groups are also known to effect an entrance 
into the wood of trees through wounds only, yet when once in, 
they spread rapidly, and at length bring about the death of their 
host. The spores of Cucurbitaria laburni were demonstrated 
by me to germinate on the laburnum, on wounds produced 
by hail and otherwise, and to send into the wood so exposed 
a mycelium, which spread through the vessels and into the rind, 
killing all the tissues on its way. Similarly Ncctria cinnabarina, 
after it has killed its host, lives thereon as a saprophyte, and 
develops patches of conidia and perithecia on the dead bark. 
Pcziza Willkommii, although really a strict parasite on the living 
rind, yet continues to grow and to reproduce itself on the dead 
branches. 

Hemi-parasites. 

If the examples already given, i.e. Mucor, PenieiUium, Botrytis, 
Pythium, are typical of hemi-saprophytes, then there may arise 
a doubt whether the remainder, the wood-destroying Polyporeae, 
Ncctria, Cucurbitaria, and Agaricus m elicits, should not be regarded 

1 Harz, Bolati. Crntra/Matl, 1HSS, Veil, xxxvi. ; Magnus, Bo tan. IVrein </. I'ror. 
Brandtiihunj, 1SS8. 


CLASSIFICATION OF PARASITES AND SAPROPHYTES. 


i 


as liemi-parasites. They must, however, be included amongst 
the hemi-saprophytes, because doubtless they are capable of 
going through their whole development as saprophytes. The 
hemi-parasites include, amongst others, the Ustilagineae, all of 
which live for a time as parasites, and cannot, even by artificial 
cultivation, be made to complete their life-history as saprophytes. 
While, however, many of the Ustilagineae are adapted to a com- 
pletely parasitic life, others can, in the form of sprouting conidia, 
live and multiply saprophytically. The conidia of Exobasidium 
and Exociscus continue to bud off conidia for a considerable time 
in nutritive solutions, yet in nature, the spores probably produce 
infecting liyphae at once, and the fungus is but little suited to 
sustain a saprophytic mode of life. Pliytoplithora infestans is 
more easily reared as a saprophyte, and occurs in nature as such, 
hence it approaches somewhat towards the hemi-saprophytes. 


True Parasites. 

The Uredineae may be taken as the most typical of the true 
parasites ; they constantly pass through their whole life-history 
on living plants, and cannot be cultivated on a dead substratum. 
So also the Erysipheae, although frequently their spores only 
reach maturity on a dead substratum, as do also those of 
Rliytisma and Polystigmci. Ergot of grain and the Sclerotinia 
inhabiting berries, are also truly parasitic, even though their 
apothecia or perithecia are produced from hibernating sclerotia, 
and though their conidia can be saprophytically cultivated on 
dead pabulum. 

The Peronosporeae and Protomyces are also true parasites. 
In many other forms the development of germ-tubes, or the 
sprouting of conidia, may be obtained in artificial nutritive 
solutions by exclusion of rival fungi and bacteria, yet it is 
doubtful whether this takes place in nature. 


§ 3. MODE OF LIFE OF THE PARASITIC FUNGI. 

The parasitic fungi may be divided according to the place of 
their occurrence and their mode of attack on the host, into two 
categories, which may be designated epiphytic and endophytic 


8 


THE PARASITIC FUNGI. 


parasites. 1 The former have their vegetative mycelium spread 
over the surface of the host-plant, the latter penetrate into the 
plant and there develop their mycelium. Both receive nourish- 
ment from the cells of the host-plants, generally by means of 
special absorptive organs inserted into the cells of the host, the 
so-called haustoria. 

We may distinguish the following groups of parasites accord- 
ing to the degree of their penetration into the organs of the 
host-plant they attack : 

1. Epiphytes: (a) with haustoria which only sink into the 
outer membranes of the host ; 

( b ) with haustoria penetrating into the cavity of the host- 
cells. 

2. Endophytes : (a) with a mycelium which grows in the 
walls of the host-cell, and is generally nourished without the aid 
of haustoria ; 

(lj) with a mycelium which grows in the intercellular spaces 
only, and is nourished with or without haustoria ; 

(c) with a mycelium which penetrates into the host-cells and 
becomes an intracellular mycelium ; 

(d) lower fungi which live completely in a host-cell. 

1. Acquisition of nutriment by the epiphytic parasitic 
fungi. The simplest mode of acquiring nutriment is found in 
yeasts (Saceharomyces apiculatus, etc.) which frequent the outside 
of living fruits, and live on the drops of sugary solution which 
diffuse therefrom. 2 

1 Epiphytic parasites always produce their reproductive organs outside their 
host-plant. In the case of endophytic parasites, the reproductive organs of 
some are produced inside the host-tissue, e .< ;. the zygospores and oospores of 
Chytridiaceae and Peronoxporear, the chlamydospores of the Ueti/agineae ; others 
form their sporocarps wholly or partially embedded, the spores and conidia only 
being discharged externally ; while a large number form sporocarps on the surface 
after the epidermis has been torn. Conidia are generally abjointed from the 
free surface of the host-plant. 

The terms epiphytic and endophytic parasites have been chosen with regard to 
the development of the parasitic food-absorbing mycelium. Some authors regard 
epiphytism somewhat differently, and include amongst endophytes those forms 
which live on the surface of the host and penetrate only by haustoria. If this be 
accepted, epiphytism is very exceptional amongst parasites of the higher plants. 
Zopf (“Die rilze”) gives as examples of this condition only the following: the 
LahouU>e.niaceae inhabiting the chitinous skeleton of certain insects, and Melano - 
xpora paraxitira on filaments of species of Imria ; these have no communication 
between the mycelium and their host. Species of Chaetoclndinm parasitic on fungi 
and absorbing the cell-wall of the host at the point of contact, could, strictly 
speaking, no longer be classed as epiphytes. 

2 Biisgen. “ Ueber einige Kigenschaften d. Keimlinge parasitischer Pilze. ” 
Botan. Zeitung, 1893. 


MODE OF LIFE OF THE PARASITIC FUNGI. 


9 


I can however hardly regard as parasites, fungi like these 
which live on an accidental outflow from plants or plant-cells, 
even though they regularly frequent places where an outflow is 
to be expected. They exert no influence on the host-plant, 
and they are nourished by substances which can no longer be 
regarded as belonging to the host. I would rather include 
them amongst non-parasitic epiphytes which, without specially 
adapting themselves, settle on any part of a living plant where 
sugary solutions suitable for their nutriment may occur. One 
might imagine however such epiphytes inducing a diffusion of 
nutritive substance from the cells of the host-epidermis to the 
closely adherent fungal hyphae ; then we should have the 
simplest mode of parasitic acquisition of nutriment on the part 
of epiphytes. They would take up food-material from the epi- 
dermal cells in much the same manner as many intercellular 
hyphae do from the adjoining walls of the host-cell. 1 

Epiphytic parasites frequenting the surface of plant-organs 
generally endeavour to increase their supply of nutriment from 
the host-cells by formation of haustoria, which pierce the cuticle 
or the whole cell-wall. Btisgen has shown experimentally 
that the adhesive discs, often formed on the germination of a 
spore, owe their origin to a contact-stimulus ; the formation and 
direction of the infecting hyphae, on the other hand, though 
depending on this, are much more determined by a stimulus 
originating from the host-cell itself. In this we have a confirma- 
tion of the accuracy of our definition of 
parasite and saprophyte. 

The appressoria, adhesion-organs or 
adhesive discs just mentioned, are char- 
acteristic of many parasites. They are 
formed chiefly on epiphytic mycelia, 
but also accompany the earlier life of 
other fungi. In the case of epiphytes, 
pores are formed on definite places of 
such an adhesive-disc, and from these 
haustoria are developed, or a hypha is 
given off and enters the host-plant to 
form a mycelium. The appressoria of the Erysipheae are very 
characteristic; in many they are broad lobed discs (Fig. 1); in 

1 Compare those cases of parasites on insects and fungi already given, p. 8 (note). 



Fig. 1 . — sp , Spore of Erysiphe a* 
umbelliferarum germinating on the 
epidermis of a host-plant ; an ad- 
hesion-disc and haustorium have been 
formed. (After De Bary.) 


10 


THE PARASITIC FUNGI. 


others, like Podosphaera castagnei, they take the form of broadened 
closely-clinging hyphae with haustoria. Frank describes a swell- 
ing of the germ-tube of Fusicladium, tremulae just before the 
infecting hypha pierces the cell- walls of its host. A similar 
phenomenon can be observed in Polystigma rubrum, in Gnomonia 
erythrostoma, and in the germinating aecidiospores of Melampsora 
Goeppertiana. Some other examples will be mentioned in our 
next section. 

Haustoria of the epiphytic Parasites. 

The most inconspicuous haustoria are those of Herpotrichia 
nigra i and Trichosphaeria parasitica, described by II. Hartig. 1 



Fin. 2. — Hauwtoria of Trichotphatria )>ava*itica. (Details on Fig. 88.) 
(After K. Hartig.) 


They are tiny hyphal processes resting on the host-epidermis, 
and sunk into the outer walls of the epidermal cells, so as to 
pierce the cuticle but not the whole wall (Fig. 2, d, c ; also 
Fig. 90). The Erysipheae are typical epiphytes, which weave 
a mycelium over the surface of plants they attack ; the 
mycelium retains its hold by adhesion -discs or appressoria, and 
from certain parts of these a fine thread-like process is given 
off, which, after piercing the epidermal wall of the host, swells 
inside to a simple or branched sac, the haustorium. The 

1 Lehrbuch <1. Haunt kmiikheiten, II. Aufl. English translation by Professor 
Somerville. Macmillan & Co., 1SJI4. 


MODE OF LIFE OF THE PARASITIC FUNGI. 


11 


haustoria of Podosphaera castagnei (Fig. 7 1 ) are bladder-like, 
those of Oidium Tuckeri are lobed. 

The simplest formation of haustoria consists in an outgrowth 
of the mycelium which depresses the cell-wall of the host 
without piercing it (e.g. Peronospora densa). In other cases the 
cell-wall, at first only depressed, becomes ultimately broken 
through. 

Certain lower fungi live parasitic on other fungi and adhere 
to their hyphae by means of well-developed adhesion-discs from 
which haustorial structures are formed inside the hyphae of the 
host. Thus Piptoceplialis fresenia is parasitic on hyphae of some 
species of Mucor, and produces from a swollen bulb-like appres- 
sorium a tuft of very fine haustoria inside the Mucor- hypha. 
Syncephalis proceeds even further, for the haustorial process grows 
and branches inside the host, becoming, in fact, an endophytic 
mycelium. A further advance towards endophytic parasitism 
is presented by the Chytridiaceae, low forms of fungi living 
on algae or fungi ; some send haustorial structures into their 
host, others develop a mycelium whose attack however is 
directed against only one host-cell. Fischer, in his “ Phycomy- 
cetes,” thus describes the latter forms : “ The vegetative body, 
a resting swarmspore, consists of a spherical or ellipsoidal part 
which becomes a sporangium, and of a filamentous vegetative 
portion which spreads through the host-cell as a haustorium or 
mycelium and dies away after the formation of the sporangium. 
This primitive mycelium is unicellular, and may be unbranched 
or very finely branched.” 

2. Acquisition of nutriment by the endophytic parasitic 

fungi. The simplest case of the endophytic mode of life is 
presented by those fungi which vegetate in the epidermal 
membranes of their hosts, and derive their nutriment osmotically 
through the inner cell-walls. They live covered by the cuticle, 
which must have been penetrated by an infecting hypha at the 
time of first attack. This mode of life is exhibited by many 
fungi, particularly by the Exoasccae ; the mycelium of these 
vegetates under the cuticle of the host plant, and ruptures it at 
the time of ascus-formation. In spite of their limited distri- 
bution the species of this group so influence the development 
of their hosts as to induce pustule-like outgrowths, crumpling 
and distortion of leaves, and even “witches’ brooms.” In some 


12 


THE PARASITIC FUNGI. 


of the Exocisceae the bases of the asci penetrate deeply between 
the walls of the epidermal cells, so forming an intermediate 
stage leading to other Exoasccac and endophytic fungi, with a 
mycelium growing between, or in the cells of tissues which lie 
deeper than the epidermis. 

The mycelium of Cycloconium oleaginum grows in the epi- 
dermal cell-membranes, branching dichotomously under the 
cuticle and sending through it erect hyphal branches for pro- 
duction of conidia. 1 The germinating conidia of Sphacdoma 
avipelinum are said by De Bary to penetrate the cuticle, and 
to produce a mycelium which spreads thereunder and breaks 
out just before formation of conidia. Mycoixlea parasitica, an 
alga, lives under the cuticle of leaves of Then and Camellia. 

We have next to consider fungi with a mycelium which 
lives and multiplies in the intercellular spaces of living plants. 
Like the Ecoasceae just mentioned, they push their way between 
neighbouring cells and spread through the already existing 
intercellular spaces. Numerous Uredineae behave in this way, 
and towards the period of reproduction the mycelium is capable 
of increasing so much that the cells of the host-tissues become 
isolated and even displaced. The various species of Hystcrium 
have an intercellular mycelium, which kills those cells with 
which it comes in contact. Certain forms, e.g. Caeoma pinitor- 
quurri and Peridermium pini (Fig. 247) possess a mycelium 
which, while still intercellular, sends off here and there little 
lateral branches into the host-cells. It is an easy step from 
forms like these to forms whose mycelium is no longer strictly 
intercellular, but derives nutriment by means of specialised 
haustoria. 

Haustoria of the endophytic Parasites. 

A large number of endophytic parasites frequenting hosts which 
do not immediately succumb to their attack, possess “haustoria” 
or special organs for the acquisition of nutriment from the 
cells of the host. The haustoria are lateral outgrowths of the 
mycelium with a limited period of growth and a more or less 
constant form. They are more varied in form, but otherwise 
quite comparable with haustoria of the epiphytes, especially 
with those of the Erysipheae. One of the simplest forms of 

1 Figures in Futujhi Paraxial, Cavara and Briosi. 


MODE OF LIFE OF THE PARASITIC FUNGI. 


13 


haustorium on an endophytic mycelium is that exhibited by 
the parasite Cystopus ; the hypliae send oft' very fine filaments 
which penetrate the walls of a host-cell and swell up to little 
button-like sacs. Many Peronosporeae (P. pygmaea , P. nivea, 
P. viticola and Phytophthora omnivorci) have haustoria of the 
form just described, whereas others have them thread-like and 
branched (P. calotheca of the woodruff), or crenately lobed (P. 
'parasitica). 

Amongst the species of Uredineae and Ustilagineae, haustoria 
are not uncommon and present many varied forms. They are, 
however, few in number, or confined to certain parts of the 
mycelium, so that they may be easily overlooked. 

Haustoria in the form of long sacs of various lengths are 
produced by Melampsora Goeppcrtiana in the tissues of both 
cowberry and fir-needle. Gymnosporangium in juniper has 
occasionally very delicate button-like haustoria. Endophyllum 
sempervivi in the house-leek has haustorial branches which, 
according to Zopf, are coiled together and anastomose frequently 
with each other. Tvhurcinia amongst the Ustilagineae possesses 
short branched haustoria resembling one-sided clusters, and 
Melanotaenium endogenum has similar haustorial-tufts even more 
branched . 1 Urocystis pompliolygodes in Hepatica triloba has spirally 
coiled haustorial hvphae, while Tilletia endophylla, Sorosporium 
saponciriac , 2 and many species of Ustilago, have haustoria with 
the form of knotted hypliae. 

Amongst the Hymenomycetes, Exobasidium vaccinii forms 
a mycelium which permeates the host-tissues with numerous 
hypliae, but the only haustoria are hypliae which here and 
there penetrate into a cell. No haustoria have as yet 
been found amongst the Basidiomycetes , 3 Pyrenomycetes, or 
Discomycetes. The two groups last-mentioned have an inter- 
cellular or intracellular mycelium, which as a rule quickly 
kills all cells with which it comes in contact. 

1 Senckenbergische naturforsch. Ges. Abhandl. 1880. Plates I. and IV. 

2 Pringsheim’s Jahrbuch, 1869. Plates VII., VIII. 

3 Sarauw has figured haustoria in mycorhiza of beech, without however- 
determining exactly whether they belonged to a Hymenomycete. Reess also 
figures similar organs on mycorhiza produced by one of the Tuberaceae. 


CHAPTER II. 

REACTION OF HOST TO PARASITIC ATTACK. 

The reaction of the host to the attacks of parasitic fungi is 
fairly constant for the same host and fungus. The various 
fungi, however, exert on the same host-plant each an influence 
of its own, while different host-plants behave very differently 
under attacks of the same fungus. 


§ 4. EFFECT OF PARASITIC FUNGI ON THEIR HOST. 1 

A. Killing of Host-Cells . 2 

1. Absorption of living cell-content by parasitic fungi. 

The lower fungi give us examples of the simplest mode in 
which fungus-parasites draw nutriment from their host-cells ; 
particularly those forms parasitic on algae or other fungi. 
The most primitive of all are numerous species which, applying 
themselves to a host-cell, bore through its walls and enter 
the cavity. There they derive nutriment at the cost of the 
living cell-content, — the plasma, cell-sap, chloroplasts, starch 
grains, etc., — and finally kill the cell. The host-cell does 
not survive the later development and reproduction of the 
parasite. The effect of the fungus is however limited to the 

1 Billroth (“uljer die Einwirkungen lebender Pllanzen und Thieraellen aufeinan- 
der,” Sammhnig Medic. Schriflen. Wiener Min. Wochenblatt, IMHt), compares in a 
masterly way the effects of micro-organisms and of injuries on animal and vege- 
table tissues. He employs Virchow's terms “ formative stimulus ” and “ formative 
irritability” ; the former to denote the capacity of micro-organisms in producing 
outgrowths of definite form or the formation of new tissues ; the latter, the 
capacity of the tissues to react to such stimuli, and to produce outgrowths, 
etc. A comparison of the external phenomena of fungoid diseases in the case 
of animals and plants recently formed the subject of a short paper by Lewiu. 

2 Pernieiasmus. 


EFFECT OF PARASITIC FUNGI ON THEIR HOST. 


15 


cell attacked which is at once killed before it can enlarge or 
otherwise react to the influence of the intruder. Good examples 
of such parasites are presented by some of the Chytridiaceae 
— the Archimycetes of Fischer — which, as a rule, inhabit only 
isolated cells of their respective host-plants. This mode of 
nutrition is equivalent to that of the Myxomycetes and Mycetozoa, 
which absorb the cell-contents after completely enveloping the 
living cell, or after slipping inside or sending a haustorial process 
into it. 

A second series of parasites consists of those which live 
on the contents of the host-cell, and give it time to react to 
the stimulus exerted by the intruder. The reaction generally 
results in a cell-enlargement or fungus-gall, which in the simpler 
cases includes one cell only. The gall harbours one or more 
parasites, which gradually use up the cell-contents. As examples 
we have Olpidium tumaefaciens and 0. uredinis, 1 Pseudolpidium 
saprolegniae, Olpidiopsis saprolegniae, Bhizomyxa hypogaea , 2 etc. 
A specially striking case is that of Pleotrachclus fulgens, which 
causes the rudiment of the sporangiophore of Pdoboliis Kleinii 
to become hypertrophied and gall-like. 3 

We have as a third series those parasites which penetrate 
into living cells and absorb their contents, at the same time 
stimulating the host-cell to abnormal and increased growth, as 
well as some surrounding cells not directly in contact with the 
fungus. In this case the parasite exerts a far-reaching effect, 
and produces a gall composed of more than one cell. Species of 
Synchytrium are examples. The fungus itself penetrates into one 
cell only, which enlarges ; but simultaneously the surrounding 
cells grow and multiply to form a wall or rampart enclosing the 
cell originally attacked. Other parasites do not absorb the 
host-contents as a whole, but only withdraw osmotic substances 
by means of delicate processes of the fungus-hyphae. These 
haustoria penetrate the wall of the host-cell, but the fungal 
protoplasm inside them remains separated from the host-proto- 
plasm by a delicate membrane. In the case of the vine-mildew 
and some other Erysipheae, the cells thus preyed on turn brown 
and die. With other related forms (e.g. Sphacrotheca castagnci), 

1 See Fischer’s Phycomycetes. 

2 This causes a slight swelling of the root-hairs of various plants and absorbs 
their content. 

3 Zopf, Beitrage zur Physiol, u. Morphol. nied. Orgcinismen, ii. 1892. 


16 


REACTION OF HOST TO PARASITIC ATTACK. 


absorption by haustoria results in a deformation and distortion 
of attacked organs, which embraces even cells far distant from 
the point of attack, yet without death following directly to 
any cell. 

2. Absorption of cells or tissues by parasitic fungi. The 

total absorption of cells or tissues by parasitic fungi constitutes 
a special form of cell-destruction. Cases of this kind occur 
particularly amongst the Ustilagineae. Thus Urocystis violae so 
stimulates the cells of Viola that they divide and produce a 
delicate tissue, rich in protoplasm ; this nutritive tissue is used 
up when spores are formed, but without any great detriment to 
the host-plant. At the time of spore-formation of other Ustila- 
gineae a great destruction of the host-tissues may, however, 
take place ; this is especially marked in attacks of Ustilago 
maydis, U. avenae, Tilletia tritici, on the ovaries of their 
respective hosts, as well as in other cases to be considered 
later. 

3. Killing of host-cells and tissues by fungi which excrete 
ferments. The simplest case under this heading is presented 
by species of Sclerotinia studied by De Bary, c.rj. Scl. sc/erotiorum. 
The mycelium of these, while still lying on the outer surface of 
the host-plant, excretes a ferment which sinks through the mem- 
branes into the cell-cavities, causing death to the protoplasm and 
even destruction of whole tissues. 

A similar process may be assumed in the case of numerous 
fungi with a mycelium which grows only in the intercellular 
spaces, yet causes immediate death to any cell it may touch. 
This is the case with many leaf-spot diseases, like those due to 
Ccrcospora, Hysterium, etc. So also do the apices of rhizomorph- 
strands kill portions of the bast of living Conifers with which 
they may come in contact. The rapid death of tissue following 
the attack of such deadly fungi as Phytophthora is probably 
due not altogether to the deprivation of nutriment, but also to 
the effects of a poisonous excretion. This, however, has not as 
yet been satisfactorily ascertained. 

B. Killing of Organs or Whole Plants. 

A large number of fungi have a mycelium which never ex- 
tends beyond a very short distance round the point of first 
infection, and causes only local disease, frequently with no 


EFFECT OF PARASITIC FUNGI ON THEIR HOST. 


17 


perceptible disturbing effect on the host. Such is the case 
particularly with leaf-spot diseases ; the tissues of isolated spots 
are killed and fall out, the leaf appearing as if perforated by 
shot, but otherwise exhibiting no discoloration or other symptom 
of disease. In contrast to these there are fungi which, directly 
or indirectly, bring about death of their host or some part of it. 

The simplest example of parasitic fungi killing their host 
directly is presented by one-celled or few-celled plants, which 
soon succumb to attack even on a single cell. Where, however, 
the host is a highly organized plant, its organs will resist the 
attack of the parasite for some time. Thus with Pliytoplithora 
fagi, the mycelium spreads rapidly through the tissues of a 
seedling, so that death ensues in a few days. Similarly species 
of Peronospora rapidly kill leaves, branches, and fruits ; likewise 
Cladosporium , Septoria parasitica, and others. 

Somewhat different in their action are those fungi which 
kill some tender part of a plant directly, and thereby in- 
directly further the death of other parts dependent thereon. 
As examples, take Pestalozzia Hartigii (Fig. 301) and Phoma 
abietina (Fig. 293), which kill only some small portion of a 
young plant or branch, but thereby cause drying-up of higher 
or distal parts. Gibbcra mccinii on stems of cowberry (Fig. 95) 
is another example. Similarly cankers arising from Nectria 
ditissima (Fig. 80), or Peziza Willkommii. Again, Agaricus 
melleus and Trametes radiciperda kill roots or lower portions of 
the stem, and bring about the death of trees of all ages. 

The case varies somewhat with certain wound-parasites like 
Nectria cinnabarina and Cucurbitaria laburni. There the my- 
celium extends so vigorously in the water-conducting organs, 
as to kill them and fill up the vessels, causing thereby so 
serious a disturbance in conduction, that branches or whole 
plants wither away in summer. The wood-destroying Polyporeae 
and Agaricini act similarly, although more slowly ; they attack 
large branches and stems, destroying all parts of the wood, 
duramen as well as sap-wood, and finally the bark. 

There are also cases where organs of the attacked host 
remain alive, but suffer on account of the hypertrophy of other 
parts. In this way portions of a plant may be killed although 
not directly the seat of the parasite. This is particularly the 
case where hypertrophied organs undergo increased growth and 


18 


REACTION OF HOST TO PARASITIC ATTACK. 


utilize the water which would otherwise have ascended to 
higher parts of the branch-system (Fig. 3). It must indeed 
be assumed that the latter are preyed on by the hypertrophied 
parts and give up plastic material, which they would otherwise 
have utilized themselves or stored up as reserve material. 
On branches attacked by mistletoe and other phanerogamous 
parasities, it can easily be observed, particularly on broad- 
leaved trees, that a supporting branch grows vigorously in the 
parts under the influence of the root-system of the parasite, 
whereas the distal parts of the same branch-system remain 
stunted and finally die. The mistletoe-bush thus comes to form 
the termination of the supporting branch. If, in consequence 
of this, the branch ceases to produce the leaves necessary in 
preparing food for it, then like every other leafless branch it 
dies. Such branches carrying leaves of the mistletoe alone may 
frequently be found on firs, pines, and broad-leaved trees ; 
even whole tree-summits have been seen on the silver fir with 
every branch terminated by a mistletoe-tuft, not unlike some 
huge candelabrum. 

In a similar manner a witches’ broom, developed from a 
lateral bud, exhibits throughout an increased growth, while the 
branch supporting it remains thin and dies from the insertion 
of the broom outwards. So also in attacks of Gymnosporangium 
on juniper it may be observed that the parts attacked have 
their growth much accelerated and many of their dormant buds 
developed, while the distal parts of the same branch die off. 
In all such cases it is quite probable that, as the distal parts 
die back, any food material which they may contain finds its 
way into the hypertrophied region. 

C. Shorten i so or Life. 

Many fungi inhabit a plant without disturbing the develop- 
ment of any part or causing immediate death, yet with such 
effect that the vegetative period of the organ in question 
terminates earlier than normally. 

A very striking example of this is presented by the needles 
of silver fir on the witches’ brooms caused by Aecidiuvi 
elatinum. The needles normally vegetate for several years, 
but when influenced by this parasite they live only a single 
season. So also needles of spruce attacked by Aecidunn cor- 


EFFECT OF PARASITIC FUNGI ON THEIR HOST. 


19 



Fig. 3. — Exoascus cerasi. Witches’ broom of cherry. The supporting branch is 
dead from its apex backwards to the seat of an infected lateral bud, which has 
developed into a witches’ broom. On the tree the supporting branch pointed 
slightly more downwards than is shewn. £ natural size. (v. Tubeuf phot.) 


20 


REACTION OF HOST TO PARASITIC ATTACK. 


means, which may, in addition, bring about death of the whole 
shoot. Needles of spruce beset by aecidia of Clirysomyxa, 
rhododendri are cast after reproduction of the fungus in August 
or September, while with Chrysomyxa abietis the needles of 
Conifers fall in May. The latter examples differ somewhat 
from the former in that the mycelium lives in the witches’ 
broom for years, and continues to send out new shoots with 
deformed needles, whereas in the Chrysomyxu attack the my- 
celium is confined to the needles and falls with them. 

Examples from other groups of fungi are the witches’ brooms 
of Alnus ineana caused by Exoascus epiphyllus. The leaves of 
these are fully developed though somewhat modified in form ; 
their life-period is, however, shorter than that of normal leaves, 
and they fall earlier. It may be observed here that this 
phenomenon of premature defoliation is one recorded as a 
consequent of many parasites. The witches’ broom twigs of 
the alder grow and produce buds almost normally, yet the 
wdiole broom-system dies in a few years, and long before the 
normal life-period of the tree. 

The war of extermination by mycelium against host-plant 
may frequently last for a very long time. Hartig gives an 
example of a larch which had carried on the combat with the 
larch-canker (Peziza Willkommii ) for over eighty years, because 
during active vegetation of the host the parasite was unable to 
make headway. 

D. Premature Development of Buds. 

The unfolding of buds in spring in advance of those of 
normal plants is also a feature of many diseased plants. This 
is manifest in the earlier unfolding of buds on witches’ brooms 
of the silver fir and cherry. The alder witches’ broom, already 
referred to, is how r ever exceptional, in that its buds open after 
those of normal twigs . 1 

A premature flowering may also result, so that flower-buds 
formed in summer unfold the same autumn instead of during the 
following spring. Thus in a recent autumn a violet opened 
in a plot in the garden of Professor Hartig in Munich. The 
flower was found to be somewhat stunted, and its stalk beset 

1 Smith, “ UntersuehunKen <1. Anat. u. Morph, der durcli Exoasceen vein 
sachten deformatiouen. ” Tnaug. Diss. Munich, 1894, p. Hi. 


EFFECT OF PARASITIC FUNGI ON THEIR HOST. 


21 


by pustules of Urocystis violae, the mycelium of which had 
perennated in the stem. Iverner in his “ Pflanzen-leben ” 1 
mentions a similar case where dowers of Primula dusiana and 
P. minima attacked by Uromyces primulcte integrifoliae unfolded 
prematurely in autumn. 

E. Preservation of the Host-Plant and of Host-Tissues. 

(Conservation.) 

In contrast to those parasites which attack a plant, or parts of 
it, and immediately kill it or otherwise exert a direct destructive 
induence, we have these which live for a longer or shorter period 
with their host without producing such an effect. Cohabitation 
of this kind may last only for a short time and terminate with 
the drst reproductive period of the fungus, or it may last for 
years as a perennating symbiosis, or as a perpetual one like that 
of lichens. 

This phenomenon is particularly conspicuous amongst the 
Uredineae. These throughout their whole development adapt 
themselves to an existence with living host-cells, so that the 
latter die only after the reproduction of the fungus. Frequently 
the mycelium lives in perennial organs for a length of time, 
even for many years. The attacked parts are of course injured 
to a certain extent, and hypertrophy of the most varied kind, 
accompanied by characteristic phenomena, may take place, yet 
this only towards the termination of the period of development. 

The Ustilagineae are in a similar manner adapted to an exis- 
tence in living organs, and there produce their spores. At the 
time of spore-formation and liberation they are deadly enemies of 
their host-tissues, yet previous to this they vegetate in the 
living tissues with little or no apparent injurious effect. Some 
like Ustilago perennans, even pass the winter in the living host- 
tissue without killing it. 

The individual species of the Hysteriaceae, Discomycetes, 
l’yrenomycetes, Hymenomycetes, and lower fungi differ very 
much in their action ; many of them inhabit living tissues for a 
length of time without injurious effect, while not a few, like the 
Exoasceae, even perennate from year to year. The galls pro- 
duced as a result of Exobasidium do not die till the fungus has 
reproduced itself. It is unnecessary at this place to give details 

1 English Edition, Natural History of Plants (Oliver), n. , p. 525. 


22 


REACTION OF HOST TO PARASITIC ATTACK. 


of other examples, since many of these will be referred to again 
in other chapters, particularly when hypertrophy is under consi- 
deration. 

§ 5. EFFECT OF PARASITIC FUNGI ON THE FORM OF 
THE HOST-PLANT. 

1. Arrest of growth, and Atrophy. While a large number 
of fungi produce more or less extensive enlargement of parts 
of their host, others cause arrest of organs, crippling, impoverished 
, nutrition, and even atrophy of 


an extreme kind. Incompletely 
developed organs of this kind 
may originate even where the 
fungus in possession produces 
only local hypertrophy. In- 
teresting examples are presented 
by many species of Synchytnum 
(e.g. S. taraxacum and S. ane- 
mones). The former is endo- 
phytic in Taraxacum, and exerts 
a stimulus resulting in increased 
growth, not limited to the 
single cell attacked, but ex- 
tending to neighbouring cells, 
which, in consequence, multiply 
and form a ring-like swelling 
round it. The leaves as a 






L 


Fig. 4. — Synchytrium taraxaci. Partial atrophy 
of laminae of Taraxacum offlcinolc. About $ 
natural size. (v. Tubeuf phot.) 


whole, however, are poorly developed, so that the lamina in 
very extreme cases may be represented only by the midrib and 
narrow margin (Fig. 4) ; while on leaves attacked on one side, 
that side alone is stunted, the other is normal. Taraxacum 
leaves badly attacked by Puccinia are not at all deformed, 
whereas those of Anemone show striking arrest of growth (Fig. 
190). Leaves of Cirsium attacked by Puccinia snavcolcns exhibit 
an arrest of the same kind, remaining less divided and of 
softer texture (Fig. 186). 

Flowers affected by parasitic fungi present many striking 
malformations. Magnus 1 describes such a case in Anemone 

* usbildung <1. befnllenen Pfl.uizen- 



EFFECT OF PARASITIC FUNGI ON THE FORM OF HOST-PLANT. 23 


ranunculoides under the influence of Aecidium punctalum. In 
the simpler cases the floral leaves were narrow, elongated, and 
greenish, stamens were formed but not carpels ; in more pro- 
nounced cases, the petals were only represented as small, simple, 



Fig. 5. — Cherry tree in blossom, with three “witches’ brooms” in foliage. 

(v. Tubeuf phot.) 

stalked, green leaves, the stamens were reduced in number and 
there were no carpels. One case exhibited, in place of a flower, 
only two leaflets terminating the flower-peduncle, one of them 
palmately divided. 


24 


REACTION OF HOST TO PARASITIC ATTACK. 


True atrophy is best seen in those cases where flower-forma- 
tion is suppressed. This effect of parasitic fungi on their host is 
by no means uncommon, the fungus alone reproducing itself, 
while the assimilating host-plant remains sterile. This atrophy 
is found not only in annual plants, but also in those where the 
symbiosis might be designated as perennial. The last-mentioned 
case is exemplified in Aecidium datinum , the witches’ broom of 
which never bears flowers ; again, by witches’ brooms of Exoasctis 



Flo. 6 . — Euphorbia Cj/parimiat. A healthy flowering normal plant compared 
with the attenuated non-flowering form inhabited by Aecidium tuphorbiat. 

(v. Tubeuf phot.) 

cerasi (Fig. 5), which bears only leaves when the rest of the 
tree is in blossom. Another perennial symbiosis behaving thus 
is shown in Euphorbia Cj/parissias attacked by Aecidium 
euphorbiae ; year after year the diseased shoots produce only 
leaves, which assist in the reproduction of the fungus (Fig. G). 
Similarly with many other Uredineae. 

Arrest of the seed occurs in ovaries of species of Primus under 
the influence of Eroasci (Fig. 7). In flowers attacked by Ci/stopus 



EFFECT OF PARASITIC FUNGI ON THE FORM OF HOST-PLANT. 25 

the ovules become atrophied, whereas the rest of the flower 
is hypertrophied. Similarly with 
flowers of cowberry deformed by 
Exobasidium. 

2. Hypertrophy. — Many para- 
sitic fungi cause abnormal enlarge- 
ment or other malformation of 
plants which they attack. The 
simplest case of hypertrophy is 
seen in the enlargement of a uni- 
cellular plant as a result of an 
endophytic parasite, e.g. Pilobolus 
Kleinii with Pleotrachclus. 

The same example is also the 
simplest possible case of a gall 
caused by a plant, and distin- 
guished by the name of “ fungus- 
galls ” or Mycocecidia, from Zooce- 
cidia, the galls caused by animals. 

Larger galls occur on leaves 
attacked by Synchytrium, where 
not only the single cell attacked 
becomes enlarged, but also the surrounding cells ; these galls, 
however, form but tiny points on diseased leaves. Similar 
small and local enlargements of the leaf-cells, accompanied 
frequently by cell multiplication, are caused by many other 
fungi, e.g. species of Exoascus. More extensive malformation may 
embrace some part or even the whole leaf, so that it is more 
or less enlarged and beset with blister-like outgrowths, as with 
other Exoasceae (see Figs. 62 and 64). Other gall-forms are 
presented by Exobasidium on the alpine-rose (Fig. 259), where 
the gall is always localized to a small area of the leaf, and 
on the cowberry, where the gall may extend over whole leaves, 
and even include the shoot (Fig. 256). 

Hypertrophy of the whole shoot, resulting in elongation and 
thickening of the twigs, is a phenomenon frequently met with 
in the “ witches’ brooms,” to be referred to later. And just 
as entire branch-systems may become hypertrophied and elon- 
gated, so may whole plants, if the mycelium, instead of remaining 
localized, spreads throughout the plant. Examples of this will 



Fig. 7. — Fruit of plum deformed by 
Exoascus pruni ; the stone is shrivelled 
and abortive, i natural size. (v. Tubeuf 
phot.) 


26 


REACTION OF HOST TO PARASITIC ATTACK. 


be described when we consider Euphorbia with Aecidium 
evphorbiae (Fig. 6), house-leek with Endophyllum, anemone with 
Aecidium (Fig. 190), and cowberry with Calyptospora (Fig. 202). 
Where plants, like the cowberry and anemone, live in com- 
munities, then these elongated individuals rise above their 
healthy neighbours, and the fructifying fungus has a better 
chance of having its spores distributed by wind. It must, 
however, be observed that when hypertrophy of a whole shoot 
or plant occurs, every part need not be enlarged to a propor- 
tionate extent ; in fact some parts generally remain abnormally 
small, e.g. leaves in cases of rusts upon cowberry, fir, anemone, 
and others. On the other hand, both shoots and leaves may 
be abnormally enlarged, as in cases of alder with Exoascus 
Tosquinetii or Ex. epiphyllus. 1 

Hypertrophy of the roots occurs on alder, where large tubers 
are produced by Frankia (Fig. 21). On Leguminosae, tubercles 
of various sizes are caused by Rhizobium (Fig. 22). Foots 
of Juncus develop thick-lobed outgrowths as a result of Schinzia 
(Fig. 179). Foots of turnip infested by Plasmodiophora have 
irregular swellings of all sizes (Fig. 315). Mycorhiza frequently 
exhibit tubercles or balls formed by the massing together of 
very short dichotomously branched rootlets into clumps (Fig. 18). 
Cycad-roots, under the influence of Rhizobium and Nostoc, also 
exhibit hypertrophy. 2 

We shall now proceed to consider hypertrophy of the repro- 
ductive organs, and at the same time to notice some other 
changes induced in the flower by parasitic fungi. 

Influence of parasitic fungi on the development of reproductive organs 

of host-plant. 

Disease of the flower and fruit, when not caused by fungi 
which kill the cell, generally causes striking floral malformation. 
These we may group as follows : 

1. Atrophy or total suppression of flowers. 

2. Arrested development of flowers. 

3. Development of rudimentary organs. 

4. Abnormal formation of flowers. 

5. Hypertrophy of parts. 

G. Transformation into sclerotia. 

'See also § 7. 3 Schneider, Botanical Gazette, 1 SiH, p. 25. 


EFFECT OF PARASITIC FUNGI ON THE FORM OF HOST-PLANT. 27 


The two first cases have already been considered. The arrest 
of the flowers of anemone, as a result of Aecidium punctatum, 
is a further example of Case 2, and at the same time exemplifies 
Case 4, in that the floral leaves become green foliage leaves, 
though of a very stunted kind. The petals of Cruciferae hyper- 
trophied under the influence of Cystopus candidus often become 
green, and at the same time much altered in shape. 

A particularly interesting case is presented by the develop- 
ment of the stamens of the pistillate flowers of Lychnis clioica 
infested by the mycelium of Ustilayo violacea. These stamens 
normally remain rudimentary, but in the diseased abnormal 
flowers become fully developed like those of the staminate 
flowers, except that the spores of the parasite replace the 
pollen in the anthers. Giard 1 has designated this phenomenon 
as “ castration parasitaire,” and he distinguishes three modifica- 
tions amongst unisexual flowers. 

(a) Stamens appear in pistillate flowers (“androgene castration 
parasitaire ”). This occurs, as already mentioned, in pistillate 
flowers of Lychnis dioica frequented by Ustilayo. 

(h) Ovaries are developed in staminate flowers (“ castration 
thelygen ”). Examples : Carex praecox with Ustilayo caricis, 
Buchlo'e dactyloides with Tilletia huclilo'eana, and Andropoyon 
provincialis w’ith Ustilayo andropoyonis. 

(c) In flowers of either sex the sexual organs of the other 
appear in consequence of the influence of the parasite (“amphigene 
castration parasitaire ”). Giard compares these cases with that 
of the development of the organs of the latent sex in animals, 
e.y. of cock’s feathers on an old hen, or growth of horns on 
castrated or “ gimmer ” animals. In both cases the phenomenon 
is due to the same cause; in the animals the organs of the 
latent sex appear as the result of the normal organs becoming 
functionless or being destroyed by castration ; in the plants 
through stimulation of the latent rudiments by the fungus, 
which does not, however, cause suppression of the organs 
already present. In some respects the phenomenon is comparable 
with what happens when the terminal shoot of a tree is lost 
and some neighbouring lateral shoot turns vertically upward 
to replace it. 

The effect of fungi on the reproductive organs of plants 
1 Mangin and Giard, Bulletin scient. de la France et de la Behjique, 1884. 


28 


REACTION OF HOST TO PARASITIC ATTACK. 


may also be seen amongst lower cryptogamic plants, two cases 
of which may be mentioned here. 1 Pleotrachelus fulgens, 
inhabiting the mycelium of Pilobolus Klcinii, causes the 
formation of galls and the suppression of sporangia, while at 
the same time zygospores, normally rare, occur in large 
numbers. Likewise a species of Syncephalis parasitic in Pilobolus 
crystallinus causes suppression of sporangia and stimulates 
formation of zygospores. 

The transformation of floral organs may resemble that observed 
by Ue Bary, in which, as a result of attack of Peronospora 
violacea on Knautia arvcnsis, the stamens appeared in the form 
of violet petals. Doubling of flowers is also caused, as in 
Saponaria officinalis, under the influence of Ustilago saponariae, 
and Cornpositae with Peronospora radii. 

The L^stilagineae, perhaps, cause the greatest amount of varia- 
tion on the flower, because many of them produce their spores 
in the floral organs of their host. Thus, in the anthers live 
Ustilago violacea, holostei, scabiosae, intermedia, svccisac, betonicae, 
major, scorzonerac, capensis, pinguicolae, Vaillantii, and Tuburcinia 
primulicola ; the last named also occurs in ovaries and stigma. 
So also do many others inhabit the ovary or some other part. 
Many, like Ustilago maydis, form spores throughout the plant 
as well as in the flower, and bring about hypertrophy and 
destruction of parts. Amongst these are Ustilago averuu, 
perennans, hordci, nuda, tritici, panici miliacei, rciliaua, cruenta, 
sorghi, Cramer i, caricis, tragopogonis, Tillctia laevis, etc. 

Cystopus (Fig. 35) causes very characteristic hypertrophy 
of all parts of the flower, particularly an enormous outgrowth 
of the ovaries and floral envelopes, whereas other parts are 
arrested in their growth. Wakker investigated a number of 
Cruciferae with flowers deformed by this parasite, and fount! 
variations in the form and anatomy of the deformations 
produced on the different host-species. 

Ecobasidium also causes well-marked hypertrophy of flowers, 
and even of the whole inflorescence of cowberry. Woronin 2 
describes and figures such cases (Fig. 25G). All parts of 
the flower may lie attacked and grow to a great size, becoming 

'Zopf., Beilrdye -.nr Physiol, und .1 for/ih. niederer Oiyanismrn, 1 892. 

Zopf., “zur Kenntniss d. Infections-Krankheiten nied. Thiere u. Pflaneen.” 
Xora Ar/u d. k. Leon. -Carol. D. Akad. Halle.. 18S8, p. 35(5. 

- Naturforsch. Gesellschaft Freiburg-i.-B., 1867. 


EFFECT OF PARASITIC FUNGI ON THE FORM OF HOST-PLANT. 29 


at the same time fleshy and of a bright rose-red colour ; the 
ovules are sterile or abnormally formed. Wakker, however, 
found no very marked change in the anatomical structure of 
such flowers. 

The species of the Exoasceae also produce striking hypertrophy 
of flowers. Thus there are the sac-like outgrowths of the 
catkin-scales or ovaries of poplar caused by Taplirina Joliansonii 
and T. rhizophora (Fig. 52), and the “pocket-plums” or “fools” 
due to Exoascus pruni (Figs. 49 and 51). In these last- 
mentioned cases, the outer layers of the ovary become thick and 
fleshy, sometimes remaining green, while the stone and kernel 
remain rudimentary. The alder, under the influence of Exoascus 
alni incanae, has the catkin-scales much enlarged, deprived of 
chlorophyll, and of a red colour (Fig. 53). 

Mummification, or the transformation of the fruit into a fungal 
resting-body or sclerotium, is not unfrequent. In some respects 
this process resembles the change in ovaries brought about by 
Ustilagineae. Here, however, we have to do neither with hyper- 
trophy of the fruit, nor yet with its complete destruction. The 
best-known sclerotium is that of Claviceps purpurea (Fig. 84). 
It first fills up the base of the ovary, then kills it and grows 
out as a large horn-like sclerotium. The sclerotium of the oak 
{Sclerotinia Batschiana) completely replaces the acorn, leaving 
only the outer covering enclosing it. Likewise, in the mummified 
berries of bilberry, cowberry, crowberry, cranberry, and others, 
one finds the normal parts almost wholly replaced by the 
resting-mycelium of some species of Sclerotinia. 

Formation of new Organs. 

Although parasitic fungi commonly induce hypertrophy of 
existent organs and development of normal latent structures, 
they are seldom associated with formation of new organs. As 
such, however, we must regard the formation of adventitious 
buds on the fronds of Ptcris quadriaurita, Eetz, and Aspidiuni 
aristahim, Sw., under the influence of Taplirina Laurencia, 
and T. Cornu cervi, respectively. 1 Buds or bulbils of this 
kind occur normally on several species of ferns ; but in those 
just mentioned they appear only as a result of the parasite, and 
develop into structures reminding one of a witches’ broom. 

1 Giesenhagen, Flora, 1S92. 


30 


REACTION OK HOST TO PARASITIC ATTACK. 


Still more striking are certain structures resembling witches’ 
brooms, which are produced on Thujopsis dolabrata in Japan, under 
the influence of the mycelium of Caeom/x deformans (Fig. 8). 
These consist of leafless non-chlorophyllous axes, dichotomously 
branched, and with each branch ending in a disc. They arise 
from shoots or leaves of the Thujopsis where structures of the 
kind would never have arisen normally, and are wholly sub- 
servient to the reproduction of the fungus, which forms its 
sori under the epidermis of the terminal discs. 



Fig. 8. Cacoma cU/orniam. The ne#t-like structures are much-branched, 
leafless shoots with each of their twigs ending in a cacoma-disc. (v. Tubeui 
phot.) 


The galls produced by Ustilago Tratbii on Polygonum Saccha- 
linensr are particularly interesting. Here, as a result of the 
presence of the parasite, there are formed the so-called vegetative 
canker-galls, and in addition, the fruit-galls, new organs derived 
from lateral outgrowths of the host-plant, and of use only 
in the spore-formation of the Ustilago ; they contain a special 
capillitium-like tissue, and serve exclusively for the shelter and 
distribution of the fungus-spores. 



EFFECT OF PARASITIC FUNGI ON THE FORM OF HOST-PLANT. 31 

Somewhat doubtful cases are the outgrowths resembling aerial 
roots which arise on Laurus canariensis attacked by Exobasidium 
lauri. Geyler, their discoverer, regarded them as deformed stem- 
shoots, but they resemble rather the galls of the alpine-rose. 


§ 6. EFFECT OF PARASITIC FUNGI ON CELL-CONTENTS. 



The most common and, at the same time, most apparent 
effect of parasitic fungi in this direction, is the stimulation to 

cell-division and cell-multiplication. This occurs chiefly in 

young tissues, or in those still in process of growth, and gives 
rise to numerous peculiar outgrowths and swellings, some of 

which have already been referred to. 

The parenchyma of mature tissues may also exhibit secondary 
cell-division, when under the influence of a parasitic fungus. 
This I found to be the case in leaf- 

petioles of Umbellifene attacked by 
Protomyces macrosporus (Fig. 9). The 
epidermis and vascular bundles are never 
disturbed, but the intervening tissues are 
permeated by an intercellular mycelium, 
which causes the cells to divide into a 
large number of delicate-walled chambers, 

° . . . Fig. 9. — Secondary cell-division 

all containing nuclei smaller than those in parenchyma of petiole of Aego- 

. . podium as a result of Protomyces 

of neighbouring undivided cells. The macrosporus. The nuclei of the 

° . . new cells are much smaller than 

same tiling IS observed 111 plants of those of the primary cell. (Com- 
Viola odorata inhabited by Urocystis P S de 

violac ; the mature parenchymatous cells become divided up 
by means of delicate walls running in various directions into 
numerous chambers or secondary cells, which Wakker in 
describing has named “ nutritive tissue.” 1 This new tissue 
remains permanently in attacks of Protomyces, but with Uro- 
cystis it is almost completely used up during the formation 
of spores. In some diseases caused by Exoasceae, a similar 
secondary cell-division takes place ; for example, in the sub- 
epidermal parenchyma of leaves of poplar with Taphrina 
aurea (Fig. 63). 

An interesting observation was made by Rosen 2 on the direct 


1 Wakker, “ Untersuchungen. ” Pringsheim’s Jahrbuch, 1892. 

2 Rosen, Beitrdge z. Kenntniss d. Pflanzenzelle. Habil. -Schrift, 1892. 


32 


REACTION OF HOST TO PARASITIC ATTACK. 


effect of haustoria of Uredineae on the cell-nucleus. He describes 
it thus : “ The mycelium of Paccinia asarina permeates between 
the cells of the leaf-tissue of Asarum, and sends into almost 
every cell of the infected part, a short, sometimes branched, 
hypha, which serves as a haustorium. This grows in almost 
every case towards the nucleus of the host-cell, and becomes 
firmly attached thereto, or completely encloses it. The nucleus, 
in consequence, undergoes considerable deformation, sometimes 
being tightly constricted by the haustorium, or the apex of 
the hypha penetrates deep into the nucleus, pushing the nuclear 
membrane before it.” 

Enlargement of the cell-nucleus occurs, according to Frank, 
in the cells of the root-tubercles of Leguminosae caused by 
bacteria; likewise in the cells of endotrophic mycorhiza of 
orchids. Schlicht, 1 in considering the endotrophic mycorhiza of 
Paris quadrifolia, says, “ One observes here, as in the mycorhiza 
of the Orchideae, that the cell-nucleus, which is very large, can 
exist in the cell beside the fungus-tissue. The hyphae, however, 
frequently penetrate into the cell-nucleus, or surround it in 
a close network.” 2 

T1 le effect of parasitic fungi on the chlorophyll of tissues 
attacked by them is very varied. We may distinguish three 
cases, apart from those in which the parasite kills the host-cell 
and its chlorophyll along with it. In the first, the green parts 
of the plant attacked become bleached by the influence of the 
parasite, and ultimately lose their green colour; this we might 
designate “ mycetogenous chlorosis.” Examples are the galls 
of cowberry and species of rhododendron, the results of many 
Uredineae, such as Chrysomyxa rhododnul ri on spruce, Accidium 
urticae on nettle, Gyvinosporanyi um clavariacformc on hawthorn, 
and the leaf-galls due to Exoasceae. 

In the second case, there is a preservation of the chlorophyll 
in places infested by the fungus, in contrast to adjoining normal 

1 Schlicht. “Beitriigez. Kenntniss d. Verbreitung u; Bedeutungd. Mycorhizen.” 
lnaug. Diss. 1889, p. 14. 

2 Groom (“ Thiamin Aseroe and its Mycorhiza,” A minis of Botany, June, 
1895, p. 339) describes and figures a similar ease. He says, “The fungus 
enters the cell as a single slender hypha, which at once grows directly towards 
the nucleus of the host-cell.” He also mentions an observation of Professor 
Marshall Ward, “that in H< mihia of the coffee disease, the Imustoria often apply 
themselves to the nuclei of the host s cells.” (Edit.). 


EFFECT OF PARASITIC FUNGI ON CELL-CONTENTS. 


33 


parts, which become pale and die. This is exemplified in 
Cronartium asclepiadeum on the leaves of Vincetoxium, Gym- 
nosporangium davariaeforme on the quince, XJncinula aceris on 
the Norway maple, Rhytisma pundatum on Acer spicatum. 

Intermediate between these two extremes are cases where 
the chlorophyll is retained, but in much reduced quantity. For 
example, organs under the influence of Exoascus alni incanae or 
Aecidium elatinum, though still green, are pale in contrast to 
those normally deep green; leaves attacked by Peronosporeae, e.g. 
Corydalis or Anemone with Plasmopora pygmaea, and Anemone 
with Aecidium pundatum or Puccinia fusca ; leaves of Cirsium 
containing mycelium of Puccinia suaveolens ; leaves of alder 
with Exoascus epipliyllus, and many others. This paler coloura- 
tion of diseased plants is frequently an easy means of recognizing 
them amongst the healthy ones. 

The third case is that of “ mycetogenous chloranthy ” or the 
development of green colour in organs normally of some other 
colour. Wakker has proved this in the petals and stamens of 
Brassica nigra and Sisymbrium pannonicum attacked by Cystopus 
and Pcronosporci. Likewise Magnus showed its existence in 
flowers of Anemone ranunculoides with Aecidium pundatum. 

The cell-sap, in some cases of hypertrophy, assumes on the 
sunny side a rose colour ; thus in galls caused by Exobasidium 
on alpine-rose and cowberry, pear-leaves with Roestelia cancellata 
and Poly stigma rubrum, catkins of alder attacked by Exoascus , 
and galls caused by Taphrina carnea on the sweet birch. The 
epidermal galls, due to some species of Syncliytrium (S. rubro- 
cinctum, S. anemones, etc.), exhibit an intense carmine colour. 
Yellow coloration occurs, according to Wakker, in nettle, buck- 
thorn, and many plants when frequented by Uredineae. There 
may also be a yellow colour due to the yellow oily contents 
of the mycelium shining through the host-tissues, as in spruce- 
needles with Chrysomyxa abietis. 

In considering the effect of parasitic fungi on the starch- 
contents of the host-plant, two very distinct cases may be 
observed. There may be, for a time, a greater accumulation 
of starch in the attacked parts than in the normal, or the 
parasite may dissolve any starch present and utilize it at once. 

o 


34 


REACTION OF HOST TO PARASITIC ATTACK. 


Accumulation of starch is described by E. Hartig 1 in spruce- 
needles attacked by Lophodermium macrosporum. In the pre- 
sence of the fungus-mycelium, an increased production and 
storage of starch takes place at a time when it is being only 
slowly formed in normal needles. If the needles become diseased 
during May, a season when they are already full of starch, 
this remains intact in the dead cells till October, when it begins 
to be used up. 

Wakker observed accumulation of starch in comfrey with 
Aecidium aspcrifolii, in buckthorn with Accidium rhamni, in 
hawthorn with Roestelia lacerata, in Sisymbrium officinale and 
other plants with Cystopus, in roots of Brassica inhabited by 
Blasmodiophora brassica c, and in hypertrophied scales of alder 
catkins with Broascus. Many other examples are given through- 
out the literature of plant-pathology. 

Particularly noteworthy is a case of starch preservation in 
oak-wood destroyed by Bolyporus dryad c us and P. igniarius 
simultaneously. 2 In the wood infested by 
either of the fungi alone the starch is dis- 
solved, but at the boundary where the two 
meet it remains in the medullary rays ; 
these, in consequence, appear snowy white, 
and consist almost exclusively of unchanged 
starch-grains, while the lignified cell-walls 
have been converted into cellulose or com- 
pletely absorbed (Fig. 10). Loew 3 remarks in 
regard to this: “One must assume here a 
variation in the kinds of diastase, and a 
neutralizing effect of the one on the other, 
in somewhat the same manner as pepsin acts 
on tyrosin. One is also reminded of two 
optical antipodes which easily unite into an 
<>i ^Vik-wood M attroyod hy optically neutral body ” ( c.y . sugar isomers). 
stin y fun ' of * un.liKKuiv.-d The dissolution oi starch by lungi has 
(1 a ¥tt nc P h«?r rwh,te - been examined in detail by Hartig. The 
wood-destroying fungi dissolve the reserve 
starch-grains laid up in the wood-parenchyma in various ways. 
Assuming the view of Naegeli, that starch-grains consist of a 



1 Wichtige Krankheilen d. WaJdhdumcn, 1874. 

- R. Hartig, Zer»etzun<jseraclieinu)ujen, 1 STS. 

:l Loew, ()., Ein naturliches System d. G(ft- IF irknngen. Munich, 1803. 


EFFECT OF PARASITIC FUNGI ON CELL-CONTENTS. 


35 


cellulose and a granulose part, Hartig describes the process thus 
(Fig. 11). The mycelium of species like Polyporus igniarius 
gives off some ferment which dissolves the starch-grains', by cor- 
roding them from the outside inwards, so as to form holes and 
canals similar to those in 
starch-grains in process of 
dissolution in the cells of a 
sprouting potato. In others, 
e.g. Thelephora pcrdix, the 
granulose is first dissolved 
from without inwards, so that 
finally only the starch -cellulose 
remains, occupying a region 
towards the outer parts of 
the grain as a kind of husk, 
which is in time gradually 
used up. In Polyporus sulphur cu$ the operation is reversed ; 
the starch -cellulose appears to be dissolved out first, leaving 
a residue of granulose. These observations were based on 
the assumption that the starch-grain consisted of a granu- 
lose portion which turned blue with iodine, and a starch- 
cellulose portion which became yellow ; or again, on treating 
the starch-grains with dilute acids the granulose was dissolved, 
while the cellulose remained in the form of a skeleton. 
Although more recent investigations have shown that the 
cellulose-skeleton results from the action of the acids, and that 
this view of the constitution of the starch- grain was not quite 
correct, yet Hartig’s observations prove that the various fungus- 
ferments have each their own action on starch-grains ; his 
results are also supported by other facts. 

Other fungi besides Polyporeae utilize the starch of their 
host-plants, thus Phytophthora in leaves of the potato. 

The formation of calcium oxalate is influenced by action of 
parasites. From Wakker’s synopsis of the phenomena of hyper- 
trophy, we find that calcium oxalate normally present in crystal- 
sacs in leaves and flowers of Phamnus Frangula, is wanting in 
parts deformed by Accidium rliamni ; crystal-sacs are less 
abundant in diseased stems than in healthy ; the calcium oxalate 
in galls of Exobasidium is not present in crystal-sacs, as in the 
non-deformed organs, but as ill-defined solitary crystals of limited 



Fig. 11. — Starch grains from the oak, in pro- 
cess of dissolution by ferments, a., of Thelephora 
'perdix ; b , of Polyporus sulphureus ; c, of Poly- 
porus igniarius. In a and b the iodine-reaction 
is shown by shading. (After R. Hartig.) 


36 


REACTION OF HOST TO PARASITIC ATTACK. 


number ; on the other hand, crystal-sacs, normally absent, are, 
under the influence of Exoascus alni incanae, formed in hyper- 
trophied catkin-scales of alder. 

It may he here observed that calcium oxalate crystals are found in the 
mycelium of many fungi. De Bary 1 found them very common, particularly 
in the mycelium of species of Botrytis, and he remarks thereon : “ it may 
well be assumed that the oxalic acid is formed from the sugar inside the 
living oxygen-absorbing fungus-cell, but is immediately ejected therefrom 
by the carbon dioxide produced in respiration ; in other words, an oxida- 
tion-fermentation takes place in the plasma of the mycelium. The oxalic 
acid is probably separated in combination with potassium and converted 
into calcium oxalate, when calcium is present in the pabulum of the 
mycelium/’ 


g 7. EFFECT OF PARASITIC FUNGI ON THE CELL-WALL. 

The effect of the mycelial hyphae of parasitic fungi on the 
cell-wall may be either mechanical or chemical. The intra- 
cellular hyphae of fungi and the apices of the haustoria of 
intercellular fungi must penetrate through the cell-walls of their 
host, either of the epidermis, or the membranes of other cells, 
consisting of cellulose alone, or in some state of lignification . 2 

The membranes may be simply pricked, as by a fine needle, 
so that the opening, because of the elasticity of the cellulose, 
closes up again after the perforating hypha has died. This 
is the case with many Uredineae. In such cases the hypha is 
constricted in passing through the cell-wall and swells out again 
in the free cell-cavitv. Frequently, as in the case of Pcrono- 
spora densa, the haustorium will only cause a depression in the 
membrane of the cell without penetrating it. 

In addition to purely mechanical perforation of the mem- 
brane, the effect of the hyphae may also be a chemical one, so 
that the wall is dissolved and the holes produced remain long 
after the hyphae which made them have disappeared. This 
solvent effect is probably always present in cases where per- 
foration of lignified membranes takes place. It is a constant 

’ De Bary. Botan. Zeiltiny, 1SS6. 

2 De Bary. Biology ami Morphology of the Fungi. English Edition. 

H. M. Ward. “ On a lily-disease," Annals of Botany, 1SS8. 

Miyoshi. “ Die Durchbohrung v. Membranen durcn Pilze.” I'ringsht 'ini's 
Jahrbucli, Vol. 28, 1S95. 


EFFECT OF PARASITIC FUNGI ON THE CELL- WALL. 


37 


accompaniment of the attacks of wood-destroying fungi on the 
woody parts of trees and shrubs. Besides actual perforation 
of the lignified membranes of their host, the hyphae of many 
of the Polyporeae and Agaric-ini exert a solvent effect on the 
walls, which extends over a considerable area, and is evidently 
due to the excretion of some ferment. The dissolution of the 
walls takes place, moreover, in a way so characteristic for each 
species of fungus that they can be determined by it alone. From 
this it must be deduced that each wood-destroying fungus 
excretes a ferment peculiar to itself, which causes a character- 
istic dissolution of the host. Our present sources of informa- 
tion on these points are the very valuable investigations of 
Professor Eobert Hartig of Munich . 1 Some of his results will 
repay our careful consideration, but we must preface briefly 
some facts regarding the process of lignification and the forma- 
tion of heart-wood in our forest-trees. 

The elements of the wood of dicotyledonous trees and woody 
plants are derived from the cambium ; their walls consist at 
first of pure cellulose, and when lignification takes place the 
so-called incrusting substances are laid down in the thickened 
cellulose wall, particularly coniferin, vanillin, wood-gum, tannin, 
etc. ; or as they may be collectively called, lignin. The cellulose 
membrane itself is coloured lilac with chlor-zinc-iodine ; when 
lignified it no longer shows this reaction, but has others peculiar 
to itself, the best known being red coloration on treatment 
with phloroglucin and hydrochloric acid, or yellow coloration 
with aniline sulphate ; chlor-zinc-iodine colours lignified tissues 
brownish-yellow. Copper-ammonium-hydrate dissolves cellulose 
but not wood . 2 If the incrusting substances be removed from 
the lignified membranes by treatment with Schulze’s solution, 
caustic soda, or other solvent, the cellulose remains and reacts 
as such. In the process of conversion of alburnum into dura- 

1 The most important of these works are : 

Die Zemeimingserscheinungen d. Holzes d. Xadelholzer u. d. Eiche. With 21 
coloured plates. Springer, Berlin, 1S7S. 

Der echte Hausschwamm, Merulius lachrymam, 18S5. 

Wichtige Krankheiten d. Waldbaume, 1S74. 

Lehrbuch d. Baumkrankheiten, I. and II. Edition, 1882 and 1889. English 
translation of II. Edit, by Prof. W. Somerville. 

Lehrbuch d. Anatomie u. Physiologic d. Pjlanzen, 1891. 

- For further reactions see : 

Zimmermann. Die bot anise he Microtechnik. 1892. 

Strasburger. Das botanische Praktikum, 18S7. English Edition, 1889. 


38 


REACTION OF HOST TO PARASITIC ATTACK. 


men other substances make their appearance in the lignified 
walls, chiefly tinctorial phlobaphenes. 

The walls of the wood-elements are, however, not lignified 
to the same extent. The primary layer of the wall is, as a 
rule, lignified most and contains but little cellulose. In con- 
sequence, on treatment with lignin-solvents, it becomes first 
dissolved while the secondary and tertiary membranes, although 
their lignin is also partially dissolved out, remain behind as a 
distinct framework of cellulose. With longer treatment destruc- 
tion of the tissue proceeds till only the pure cellulose membranes 
of the isolated cells remain. The ferments of many fungi act 
in this way; for example Trametcs pini, as shown in Fig. 12; 
at a the wall is in its normal condition, showing a primary 



Fig. 12. —Section of trachcide# of pine-wood in proce.ss of dissolution l>y the 
ferment of Tramete* pini. (After R. Hartig.) 


wall and two striated secondary membranes; at h the fungus- 
ferment has caused a splitting of the primary wall, which 
formerly appeared as a single layer, and the elements are 
separating from each other ; the “filling-material" of the inter- 
cellular spaces (under c), and the ring of lime surrounding the 
cavity of the pit d, remain for a longer time; the right wall 
of the cell b consists only of cellulose, (as indicated by the 
striation being no longer shown, although still present); in 
the cell <• the primary wall has disappeared, and the secondary 
and tertiary membranes thin off towards f in which only 
the ash constituents remain as fine granules, better seen in 
Fig. 1 3. 

In contrast to the lignin-dissolving fungi, there are those 
which dissolve cellulose. When wood is treated with sulphuric 


EFFECT OF PARASITIC FUNGI ON THE CELL-WALL. 


acid the cellulose is dissolved out, and the primary wall remains 
almost intact, while the secondary after swelling is converted 
into sugar and gum. Certain fungi (e.g. Polyporus vaporarius, 
P. Schweinitzii and P. sulphureus), act in the same manner, 
first dissolving out and consuming the cellulose before attacking 
the wood-gum. When wood is destroyed by fungi of this 



^ 6 
Fig. 13. 


Fig. 14. 


Fig. 13. — Tracheid of Pinus sylrestris destroyed by Trametes pint. The primary 
cell-wall is completely dissolved from below upwards to a, a ; b, secondary and 
tertiary layers of the walls consisting in the under portion of cellulose only, in 
which granules of chalk are recognizable ; c , fungus -hyphae boring through the 
walls, leaving holes d and e. (After R. Hartig.) 

Fig. 14. — Tracheid of Pinus destroyed by Polyporus Schweinitzii. The cellulose 
has been extracted, and the wall consists only of wood-gum. The fissures are a 
result of drying-up, but they do not extend into the primary wall a, b. Crossing 
of the fissures takes place at the bordered pits c, and at the bore-holes d and e ; 
/, simple fissures. (After R. Hartig.) 


kind, the primary wall, containing but little cellulose, is hardly 
affected, and the secondary membranes shrink together, so that 
numerous fissures are produced running in a spiral direction, 
corresponding with that of the stratification (Figs. 13 and 14.) 
The tertiary membrane varies in its nature ; it may consist of 
pure cellulose or be more or less lignified, or even cuticularized. 
In the wood-fibres of some plants ( Cytisus , PTumulus,) this 


40 


REACTION OF HOST TO PARASITIC ATTACK. 


layer becomes normally loosened from the other membranes, and 
appears as a separate tube in the cavity of the fibre. 

Variations of this kind in the structure of the wood must of 
course influence the action of the attacking fungus. The decay 
may be a local one, as with Trametes pint, T. raclicipcrda, 
Thelephora pcrdix, which cause destruction of isolated spots 
only and produce holes here and there throughout the wood. 
On the other hand, the wood may be uniformly converted into 
a discoloured decayed mass. The walls may be simply pierced 
by little holes corresponding to the perforating hypha, or large 
portions of them may be more or less completely dissolved 
away, and either the cellulose or lignin remain behind as a 
skeleton. Hartig gives an interesting case which accompanies 
dry-rot (. Merulius lacrymam ) ; the mycelium adherent to the 
cell-walls dissolves out the lime granules included in the mem- 
branes by the excretion of some fluid containing carbonic (or 
other weak) acid, in much the same way as roots corrode 
limestone. 

The dissolution of starch in wood has already been considered. 

In conclusion should be mentioned Ilartig’s observation 
that normal spruce wood, on treatment with ferric chloride, 
the reagent for tannin, gives no coloration, such as is given 
by the same wood when destroyed by dry-rot. 

§ 8. EFFECTS OF PARASITIC FUNGI ON THE ANATOMICAL 
STRUCTURE OF THEIR HOSTS. 

Effects of this kind can only be looked for where mor- 
phological changes have resulted from the presence of parasitic 
fungi, particularly in the case of hypertrophied organs. Wakker 1 
was the first to collect recorded evidence of anatomical changes 
due to hypertrophy ; he added to these by his own investi- 
gations, and classified the results. We shall therefore in this 
division depend chiefly on his publications. 

Enlargement of host-cells is one of the most frequent pheno- 
mena accompanying attacks of parasitic fungi. It may take 
place with both intracellular and extracellular parasites. 

A single cell hypertrophied in this way is the simplest 
possible form of a “fungus-gall” (see p. 25). Examples of 

’Wnkker, Priwj.iheim'* Jahrbuch, 1 892. 


EFFECTS OF PARASITIC FUNGI ON TISSUES OF HOST. 


41 


simple galls of this kind are cells of Pilobulus Kleinii inhabited 
by Pleotrachelus fulgcns, cells of turnip infested by Plasmodio -• 
phora, or of dandelion with Synchytrium. 

Cell-enlargement resulting from the influence of extracellular 
parasites is most distinctly seen in those algal cells, which 
form lichens with the hyphae of certain fungi. Thus according 
to Stahl, the algal cells of the lichen Endocarpon pusillum 
become enlarged six-fold. 

Cell-enlargement accompanies all hypertrophy of plant organs, 
whether the parasite lives purely intercellular, or has haustoria. 
At the same time one generally finds a disappearance of the 
intercellular spaces present in the normal tissues ; in some 
special cases, however, these may become more numerous and 
larger. Cell-enlargement, accompanied by disappearance of 
normal intercellular spaces and chlorophyll, are shown by 
Woronin’s illustrations to be very marked in the galls on cow- 
berry, due to Exobasidium vaccinii. Cell-enlargement is also 
frequent in cases of hypertrophy due to Exoasceae ; thus in 
Taphrina aurea, although the mycelium is only subcuticular 
or penetrates but slightly into the epidermal layer, yet the 
cells are much enlarged and their walls are strikingly thickened 
(Fig. 63). Smith 1 found that when leaves became thickened 
in consequence of attacks of certain species of Taphrina, their 
cells became larger and rounder, so that the large intercellular 
spaces of the spongy parenchyma disappeared and the char- 
acteristic appearance of that tissue was lost. 

The epidermis, as has already been indicated, is influenced 
by fungi which live between the cuticle and cell-wall, as well 
as by epiphytic fungi, whose haustoria penetrate it. The 
epidermis is, however, jnore frequently destroyed by endophytes, 
which rupture it in forming their reproductive organs. Some 
of these produce their sporocarps inside the epidermal cells, 
and, as they enlarge, cause detachment of the outer walls of 
the cells from the remainder, to form for a time a covering 
which is ultimately ruptured as the sporocarps attain maturity. 
Where the fungi live under the cuticle (e.y. the Exoasceae), 
this alone is ruptured when the asci are formed. The repro- 

1 William G. Smith. “ Untersuchung cl. Morphologie u. Anatomle cl. (lurch 
Exoasceen verursachten Deformationen. ” Inaug. Dissertation, Munich, 1894; 
also, Forstlich-naturwisn. ZeiUchrift, 1894. 


42 


REACTION OF HOST TO PARASITIC ATTACK. 


ductive mycelium of the following forms also grows only under 
the cuticle : Rhytisma andromedae, the spermogonial mycelium 
of Puccinia anemone s, Phragmidium, and other Uredineae. 

In many cases of hypertrophy the epidermal cells become 
enlarged in a radial direction, and this, as in Taphrina aurea, 
may be accompanied by considerable thickening of the walls. 
In other cases, like that produced by Synchytrium, the epidermal 
cells may become gelatinous. 

The cork becomes abnormally increased in many examples of 
hypertrophy. Thus in witches’ broom of alder due to Exoascus 
epiphylius a phelloderm is formed, while on normal twigs phellem 
alone is produced. Cork is found in juniper needles with 
Gyranejsporangivm juniper inum, though never in the normal needles. 
On the other hand, cork-formation is suppressed in twigs of 
hawthorn, deformed by Roestelia lacerata. The so-called “wound- 
cork” is constantly associated with attacks of parasitic fungi ; it 
separates diseased portions of rind and bast from sound, forms 
sheaths round bundles of sclerenchyma, and permeates the 
medullary rays. 

Collenchyma was found by Wakker to be absent in all cases 
of hypertrophy of parts of plants where it is normally present ; 
for example, in stems and petioles of cowberry attacked by 
Exobasidium, stems of buckthorn with Aecidium rhainni, of 
Crataegus with Roestelia lacerata, of nettle with Aecidium nrticae, 
and of Sanguisorbia with Xenodoch us carbonarius. On stalks of 
Uinbelliferae with pustules of Protomyces, I found, where the 
collenchyma region was involved, that that tissue was not 
developed (Fig. 46). 

In all cases of hypertrophy, parenchyma plays an important 
part. Most abnormal outgrowths result from multiplication and 
enlargement of the cells of the parenchyma, the formation of 
mechanical tissues being more or less suppressed. Thus the 
gigantic examples of hypertrophy exhibited by turnips infested 
by Plasmodioj)hora, consist almost exclusively of parenchyma. 
Thickening of stems or branches is generally due to increase 
of the rind-parenchyma, as in buckthorn under influence of 
Aecidium rhamni, hawthorn with Gym oosporangium clavariae- 
formc, in most witches’ brooms, and in many other cases. In 


EFFECTS OF PARASITIC FUNGI ON TISSUES OF HOST. 


43 


the witches’ brooms due to Accidium elatinum, the pith appears 
enlarged as the result of increase of the medullary parenchyma. 
In diseased leaves, palisade parenchyma can frequently no longer 
be distinguished from spongy, and only irregular polygonal cells 
are formed. As examples may be given needles of fir with 
Aecidium abietinum, and leaves with galls due to Exoasceae. 
Finally, there may be a marked increase of wood-parenchyma, 
both of medullary rays and the wood proper; this is especially 
well marked in Juniperus communis affected by Gymnosporangium 
junipcrinum } where in consequence of an enormous increase of 
the parenchyma of rind and medullary rays, the tracheidal 
regions become separated by broad wedge-shaped rays, and at the 
same time they are peripherally intersected by bands of paren- 
chymatous tissue resulting from increased development of the 
wood-parenchyma (Fig. 220, etc.). 

The Sclerenchyma is generally suppressed where hypertrophy 
occurs. Examples mentioned by Wakker are stems of cowberry 
with Exobasidmm, of hawthorn with Gymnosporangium, of 
Sanguisorbia with Xcnodochvs, and alder catkin-scales with 
Eoc •oascus. On the other hand, sclerenchyma is developed in 
stems of Cirsium as a result of Puccinia suaveolens, whereas 
normally it is absent. 

The secondary vessels of the wood frequently remain irregular, 
and with imperfectly absorbed partition-walls. According to 
Wakker, this is the case in Vaccinium with Exobasidium, 
Crataegus with Roestelia, and Rhammis with Acculium. 

Suppression of interfascicular cambium was observed by 
Wakker in buckthorn and nettle with their respective Aecidium 
parasites. Prolonged activity of the same tissue he found in 
Sisymbrium with Cystopus. 

Arrest of lignification was found by Wakker in medullary rays 
of Crataegus with Roestelia, and in deformed scales of alder 
catkins affected by Exoascus. 

We have already considered increased growth in length and 
thickness in connection with hypertrophy. It need only be 
added that increased thickness of woody plants may be due to 
increase of the rind, the bast, the pith, or medullary rays, and not 

1 P. Wornle. “ Anatoniische Untersuchung tl. (lurch G 3 'innosporangiuni-Arten 
hervorgerufenen Missbildungen. ” Inaug. Diss. , Miinchen, 1894; also, Forstlich- 
naturwiss. Zeituchrift , 1894. 


44 


REACTION OF HOST TO PARASITIC ATTACK. 


to increase in the actual wood elements. This is the case in 
twigs of silver fir witches’ brooms, in young swellings of juniper 
attacked by Gymnosporangium, and in the thickened twigs of 
Albizzia resulting from Uromyces Tepperianus (Fig. 181 ). There 
may be, however, a distinctly increased growth of the wood. 
Thus, with attacks of Gymnosporangium frequenting juniper, 
especially G. sabinae, there is often a marked thickening of 
branches due to increase in the xylem-elements. Again, one 
finds cankers due to Aecidium elatinum, accompanied by stern- 
swellings with a diameter twice or three times that of the 
normal, and in which the bark and bast form but a thin layer 
in proportion to the part made up by the wood. Exceptionally 
striking are the gigantic woody knots formed on the Japanese 

Pinus densiflora, and P. 
Thunbergii affected by Peri- 
dermium giganteum (Fig. 
15). 

Wakker found that mu- 
cilage canals of Pkamnus 
Frangula affected by A'cci- 
dium were not so well 
developed as in normal 
twigs. 

llesin-canals are often 
irregularly formed and ab- 
normally multiplied in con- 
sequence of parasites. The 
resin-canals of the spruce 
were found by Hartig to be so numerous in plants attacked by 
Agaricus melleus that an abnormal quantity of resin is produced 
in the wood, and Hows from the diseased roots ; hence has 
arisen the name “ resin-glut ” or “ resin-llux ” by which the 
disease has long been known. A particularly noticeable flux of 
resin takes place from pine-bark in presence of Peridennium 
pini ; the mycelium grows in the medullary rays and resin- 
canals, causing an excretion of resin from all living parenchyma 
in the wood, so that both bast and wood become completely 
impregnated with resin, and thin sections of wood transmit a 
rose-coloured light. 



Fin. 15. — Wood-swelling on Pi nus deiuijlora, attacked 
;it this place by Pcridermium giganUum. J natural size, 
(v. Tubeuf phot.) 

(On Ptnus Thualpergii still larger examples may occur.) 


CHAPTER III. 


RELATION OF PARASITE TO SUBSTRATUM. 

§ 9. EFFECT OF THE SUBSTRATUM ON THE DEVELOPMENT 
OF THE PARASITE. 

A number of parasitic fungi live only on one species of 
host. For example Sclcrotinia baccarum on Vaccinium Myrtilhis, 
Chrysomyxa abietis on Picea excelsa, Tripliragmium ulmariae on 
Spiraea ulmarici, Hysterium nervisequium on Abies pectinata, 
Rhytisma andronudae on Andromeda. polifolia. I)e Bary 1 proposed 
for cases like this the term monoxeny, while to cases in which a 
parasite frequents several different species of host he gave the 
name polyxeny, or more particularly, dixeny, trixeny, etc. As 
examples of polyxeny may be mentioned Rhytisma salicinum 
found on all species of willow, and Rhytisma acerinum on the 
genus Acer. Other parasites attack not only different species 
of some genus, but also different genera ; thus, Puccinia graminis 
occurs on various cereals and grasses, Phytophthora omnivora 
on many different plants, Phyllactinia suffulta on leaves of 
Corylus, Fagus, and many other trees ; Claviceps purpurea on a 
large number of cereals and grasses, Cystopus candidus on many 
Cruciferae, and Nectria cinnabarina on all kinds of broad-leaved 
trees. 

Monoxeny and polyxeny must be carefully distinguished from 
the autoecism and heteroeeism of the Uredineae. Many species 
of this group go through their whole life-history, and produce 
all their forms of spore on the same host, others, however, pro- 
duce some forms of spore — spermatia and aecidiospores — on one 
host, and the remainder — uredospores and teleutospores — on 
1 Botanische Zeitung, 1867, p. 264. 


46 


RELATION OF PARASITE TO SUBSTRATUM. 


another host. Such heteroecious parasites may be, however, also 
monoxeuous ; for example, Melarnpsora Goeppertiana has its 
teleutospore-fomi only on the cowberry, its aecidium-form 
only on the silver fir. On the other hand, Chrysomyxa 
rhododendri frequents several species of Rhododendron, while 
the aecidia occur only on Picea excelsa ; Cronartium asclepiadeum 
comes on both Gentiana and Cynanchum, the aecidial stage 
only on Pinus sylvestris. With Gymnosporangium clavariaeforme 
this condition is reversed, the teleutospore-form occurs only on 
Junipcrus communis, the aecidial on various species of Crataegus 
and other genera. 

The effect of various substrata on the development of any 
fungus may be most conveniently investigated : (a) on facul- 
tative parasites and saprophytes, ( b ) on polyxenous species of 
fungi, (c) in cases where the fungus inhabits essentially different 
organs or tissues of the same host. 

The most obvious effect of the substratum is presented during 
the germination of spores. The spores of most parasites ger- 
minate in water. Those of certain smut-fungi, especially in 
the fresh condition, will not germinate at all, or only to 
a very limited extent in water, whereas they will do so 
immediately and unanimously on being offered a nutritive 
solution. Til/etia, a genus of Ustilagineae, behaves, however, 
in quite the reverse way, it germinates only in water, and 
refuses to do so in nutritive solutions. Hartig found that the 
spores of dry-rot (Mcndim) would neither germinate in water 
nor in the usual nutritive solutions, but that they did so at 
once on adding alkalies to the water, such as those supplied 
by addition of urine. Very characteristic is the behaviour 
of these spores, which only germinate in contact with their 
host-plants, like many Chytridieae 1 (Synchytrium), as well as 
C'ompletoria and Protomyccs . 2 Others again send out germ-tubes 
which remain small and soon die away if an immediate 
opportunity of penetration into a host is not presented. Pe 
Bary states this to be the case with swarm-spores of Cystopus, 
Peronospora nivea, Erysipheae, etc. Amongst the Uredineae, the 
germ-tubes are short-lived : they will penetrate into almost any 

1 De Bary, Morphology nml Biology of the Fungi, chap. VII. 

- An exactly parallel case is presented by the seed of Orobancheoe, which 
germinate only in contact with the roots of their host (Koch's “ Orobanchen,” 
Heidelberg, 1887). 


EFFECT OF SUBSTRATUM ON DEVELOPMENT OF PARASITE. 


47 


host, but soon die off, if it be not a suitable one. De Bary 
also observed a germ-tube of Peronospora pygmaea, which 
frequents Anemone, making its way into Ranunculus Ficaria, 
but soon to die. Germinating spores of Cystopus candidus will 
enter the stomata on leaves of any of their host-plants, especially 
Capsclla, but will only develop further if they are successful 
in penetrating into the cotyledons. 

Variation in the substratum produces very great difference in 
the formation of the reproductive organs. Thus many Ustila- 
gineae produce conidia by continuous sprouting only when 
cultivated in nutritive solutions, while their resting-spores are 
developed only from a mycelium which inhabits the reproductive 
organs of their host ; this is the case with Ustilago caricis, 
TJ. anthearum, and U. tritici. In others the spores are found in 
all parts of the flower, and even in the inflorescence, as in 
Ustilago crucnta and T J. tragopogonis, while in Ustilago maydis 
spores are also produced in leaves and stems. 

The various parts of the same plant behave very differently in 
this respect. The Ustilagineae just considered reproduce them- 
selves only on certain organs of their host, although the 
mycelium is also present in other organs. Other fungi behaving 
similarly are Epichlo'e typhina which produces its perithecia only 
on the surface of the sheath of one of the leaves just below the 
inflorescence ; Aecidium elatinum develops its aecidia only on 
the needles of the witches’ broom ; Aecidium euphorbiae has its 
aecidia only on the leaves of its host ; Exoascus pruni has asci 
only on the fruit ; Calyptospora produces teleutospores in the 
epidermal cells of the stem, never of the leaves ; and so on in 
many other cases. 

The formation of oogonia of Cystopus exhibits a striking vari- 
ation according to the host-plant. Cystopus candidus on Capsclla 
produces conidia alone, never oogonia ; yet the latter are plenti- 
fully developed in flowers of Erassica, being confined, however, to 
the flowers, while conidia are produced in all parts. Cystopus 
bliti forms conidia only in the leaves, and oogonia only in the 
stems of Amarantlms blitum . 1 

The mycelium of many other fungi can only grow in certain 
organs, while germ-tubes from the spores are only able to pene- 
trate into certain parts of the host. Thus, Exoascus alni incancic 
1 De Bary, Morphology and Biology of the Fungi, English Edition, p. 391. 


48 


KKLATION OF PARASITE TO SUBSTRATUM. 


lias a mycelium only in catkin- scales ; Exoascus pruni, however, 
hibernates in the twigs, and forms reproductive organs only in 
the walls of the ovary ; Aecidium strobilinum grows only on the 
cone-scales of spruce; Claviceps frequents only the young ovaries 
of cereals and grasses ; and so on, other fungi inhabit only leaf, 
stem, root, or flower. 

In this connection points of considerable interest are presented 
by the behaviour of many Uredineae hitherto little investi- 
gated. As was pointed out by De Bary, the germ-tubes 
produced from both uredospores and aecidiospores (in Puccinia 
dianthi those from sporidia also), penetrate into the stomata 
of any phanerogamous plant. If, however, that should not be 
a host-plant of the fungus in question, then the germ-tubes 
die away in the stomatal air-cavity. If the host suits the 
fungus only in a limited degree, then no hypertrophy will 
result, and the latter will attain only to the formation of spermo- 
gonia. Let the host, however, be the one best suited to the 
fungus, then hypertrophy will result and aecidia be developed. 
Very conclusive evidence of this interesting condition has been 
furnished by numerous experiments which I have carried out 
with spores of Gymnosporangium } If one infects Crataegus 
Oxyacantha with C. clavariaeformc, very marked stem- hypertrophy 
results, even by the time the spermogonia have made their 
appearance ; there is also considerable swelling of leaves and 
slight enlargement of cotyledons, while aecidia are produced 
in numbers everywhere. When the same fungus is used to 
infect Pyrus Aucvparia, no yellow spots or malformation 
of any kind results, and spermogonia, hardly visible with a 
lens, are formed only here and there. A similar infection on 
Pyrus latifolia (P. Aria x torminalis) results in a crop of 
badly developed aecidia. If quince be infected, then without 
any hypertrophy whatever, little red spots bearing numerous 
spermogonia are formed on the leaves, but the development of 
the fungus ceases there ; on the death of the quince leaves, 
the chlorophyll is retained in the immediate neighbourhood of 
the spermogonial spots, so that they remain for some time as 
green islands on the yellow leaf. R. Hartig’s infections with 
Mclampsora treuudae also led to varied results ; on Pi mis there 
ensued a distinct disease ot the cortex ( Caeoma pinitorqinnn), 
1 v. Tulieuf, Centra/b/att /. liacteriolo<ji( u. Parasiteitkinide, 1891. 


EFFECT OF SUBSTRATUM ON DEVELOPMENT OF PARASITE. 49 


while on Lario : only little cushions appeared on the needles 
( Caeoma laricis). 

These variations in the effect of the substratum on the 
development and reproduction of the parasites assist us to 
understand the well-known resistance of certain varieties and 
species against epidemic diseases, which are sweeping off their 
near allies. Thus, we know that some varieties of cereals suffer 
from attacks of rust-fungi more than others grown under like 
conditions. Similarly amongst the varieties of vine some are 
known to be more sensitive to disease than others. These 
points will be more fully discussed in a subsequent chapter. 


D 


CHAPTER IV. 

NATURAL AND ARTIFICIAL INFECTION. 

§ 10. In artificial infection we have a safe mode of distinguishing 
whether a fungus is parasitic or not ; in other words, whether 
it is capable of penetrating into the organs of living plants. 
This method of investigation should always be resorted to in 
determining the cause of disease, more especially if mycelium 
or sporocarps of several fungi are present on the diseased 
material simultaneously. For it not unfrequently happens that 
the disease has made so much progress as to make it quite 
impossible to determine whether or not any fungi present on 
the dead remains are really the cause of disease. In many 
cases where one finds a mycelium in living parts, it has 
disappeared, and only sporocarps remain in portions already 
killed. 

Injuries due to insects frequently accompany fungi on a 
diseased plant, so that it is extremely difficult to say which was 
the primary cause of the damage, and artificial infection must 
be resorted to. So also with injuries from some external source 
like drought, heat, cold, moisture, and mechanical causes. 
Fungi appear so soon after hurtful agents like these, that it 
becomes doubtful whether they are the cause of the death of 
the host, or the result of it. 

Minute observations in situ of all the circumstances connected 
with the attack, combined with examination of numerous speci- 
mens and comparison with neighbouring plants, enable one, 
after some experience, to sav with a fair degree of certainty, 
whether the disease in question is of fungoid origin or not. 


NATURAL AND ARTIFICIAL INFECTION. 


51 


The exact proof, however, is best obtained by meaus of experi- 
mental infection. 

With many parasites the sporocarps are normally developed 
saprophytically on a dead substratum, so that if parasitism 
be suspected it can only be proved by infection. Thus the 
perithecia of Nectria cinnabarina develop only after the death 
of the plant-organ, which the fungus attacked when alive. The 
more complex reproductive organs of many fungi are developed 
•only on dead remains of the host, while on living or dying 
parts one finds various forms of conidia of doubtful relation- 
ship. In many cases it has been possible, by means of artificial 
culture alone, or combined with artificial infection, to prove 
various forms of reproductive organs to be stages in the life 
of the same fungus. 

When a group of fungi contains both saprophytes and parasites, 
it is often necessary to determine whether some species is para- 
sitic or purely saprophytic. This is particularly the case with the 
groups of Pyrenomycetes, Discomycetes, Hymenomycetes, several 
groups of the lower Fungi, the Bacteria, and Myxomycetes. It 
is unnecessary, however, with the Uredineae, Ustilagineae, Per- 
onosporeae, Exoasceae, and other groups known to contain 
parasites exclusively. 

But even in these last-mentioned groups experimental in- 
fection is necessary for obtaining information on other points. 
The reproductive organs of Uredineae cannot be reared in 
artificial solutions, so that their cultivation must be carried out 
on the living host-plant. In this way alone can we ascertain 
the relationship of uredospores, teleutospores, and aecidial-forms, 
where any doubt occurs as to their belonging to the same 
species. Infection becomes particularly valuable when one has 
to investigate heteroecious Uredineae, whose various forms of 
reproductive organs inhabit several host-plants. Thus it was 
by means of infection that De Bary discovered the connection of 
Aecidium berbcridis on the barberry, and Puccinia graminis on 
cereals ; likewise Hartig, the relationship of Melampsora Goep- 
pertiana on cowberry with Aecidium columnar e on needles of 
silver fir. There still remain many aecidia, teleutospores, and 
uredospores, whose related forms have not yet been found. 

Infections are also necessary to determine the species of a 
fungus. It has been found, for example, that Gymnosporangium 


52 


NATURAL AND ARTIFICIAL INFECTION. 


confusum and G. sabinnc may, in their aecidial stage, be dis- 
tinguished as two species inhabiting distinct hosts — Crataegus and 
Pyrus respectively — whereas, in their teleutospore stage on juniper, 
they scarcely vary. In infection we have an important aid in 
determining the host-plants of the various forms of heteroecious 
fungi, and in this way it has been found that the same fungus 
behaves differently according to the host-plant on which it 
is present. Thus, in the genus Gymnosporangium, I have found 
that a certain species had well-developed aecidia on one plant, 
poorly developed ones on another, while on a third only spermo- 
gonia appeared. Similarly, in that case already mentioned, 
Hartig found the Melampsora of the aspen to produce on the 
pine a disease of the cortex, accompanied by marked deformation, 
while on the larch the symptoms were mere inconspicuous aecidia 
on the needles. 

Amongst the Ustilagineae, experimental infection is necessary 
to determine whether the natural infection of host-plants results 
from germinating spores (chlamydospores), or from germinating 
conidia (sporidia). Kuhn was able by this means to demonstrate 
exactly that the spores of Ustilagineae produced germ-tubes 
capable of direct infection. Brefeld succeeded in observing the 
penetration of germinating sporidia into a host-plant. In this 
way he proved, amongst other facts, that maize may be attacked 
by Ustilago maydis on any young part ; also, that the mycelium 
remained local. Oats, on the other hand, could only be infected 
by Ustilago avenae at the neck of the young seedling, and the 
mycelium extended through the plant till it reached the inflor- 
escence, where the spores are formed. 

In the case of the Exoasceae, two points were cleared by the 
aid of artificial infection — the penetration of spores into leaves of 
host-plants, and the production of witches’ brooms. Sadebeck , 1 
by means of infections of Ecoascus epiphyl/us on Alniis iucana, has 
produced witches’ brooms artificially, thus proving that these 
malformations really originated from the mycelium of E.ivetscus. 

It is by infection-experiments that one determines into which 
part of a host the germ-tubes penetrate, whether into leaf, flower, 
fruit, stem, or root, and also whether it passes through the 
epidermis, or between two adjacent epidermal cells, or through 

1 Kritixche. (J ntersuch unt/en itber <1. durch Ta/>hriiia herroryebraehten Bainn- 
kranklueiten, 1890 . 


NATURAL AND ARTIFICIAL INFECTION. 


53 


the stomata. Also, whether the germ-tube formed from a 
germinating spore penetrates direct, or if, as shown by lie Bary 
for Sclerotinia, a mycelium vigorous enough to penetrate must 
first be developed saprophytically. 

In this connection De Bary 1 states that the germ-tubes from all aecidio- 
spores and uredospores only penetrate by stomata, and thence extend through 
the intercellular spaces. Entry through the stomata has also been observed 
on the germ-tubes from sporidia of Leptopuccinia dianthi, and from spores of 
Entyloma. On the other hand, germ-tubes from the spores of teleutospores, 
from spores of Peronosporeae, Ustilagineae, Sclerotinia, Polystigraa, Pro- 
tomyces, and Synchytrium effect an entrance through the outer cell-walls into 
the epidermal cells or stomatal guard-cells. De Bary also describes the 
peculiar behaviour of zoospores of Cystopus and Peronospora umbelliferarum, 
which, if they come to rest near a stoma, germinate, and the germ-tube 
enters therein, whereas one developed in water soon dies. Certain fungi 
penetrate sometimes through the membrane, sometimes by a stoma, e.g . — 
Phytophthora infestans, Peronospora parasitica, Exobasidium vaccinii. 

In the case of Phytophthora omnivora, Hartig found that the germ-tubes 
from the zoospores crept along the surface of the leaf till they reached a 
place where two epidermal cells adjoined ; there they entered, and only 
rarely grow into the epidermal cells. The germ-tubes of Protomyces macro- 
sporus and Tuburcinia trientalis enter their hosts in the same way. 

Front experiments, one is able to determine the conditions 
favourable, or otherwise, to infection by parasitic fungi; to ascertain 
the influence of temperature, air-rnoisture, water-content of the 
host, hairiness of the leaves, and the effect of resin or other 
excretions as protections to wounds. For example, it was in 
this way that Flartig found Salix pulchra ( pruinosa x daphnoidcs) 
to be a hybrid which, on account of its hairy leaves, is more 
resistant to Mclampsom than Salix pruinosa , 2 Much investiga- 
tion remains yet to be done in this direction to ascertain what 
varieties or species of cultivated plants are likely to be least 
liable to attack by epidemic diseases . 3 

The methods used in carrying out artificial infection are 
based on the observation of cases of natural infection. Most 
frequently infection is performed by means of spores, less often 
with mycelium. 

The spores of lower forms of fungi are generally distributed 
by means of water, especially in dew or rain. Zoospores are 

1 Morphology and Biology of the Fungi, English Edition, pp. 361-362. 

-Hartig, Diseases of Trees, English Edition, 1894, p. 171. 

3 See Chapter V. on “Disposition.” 


54 


NATURAL AND ARTIFICIAL INFECTION. 


completely adapted for distribution in water. Amongst the 
higher fungi, spore-distribution almost always takes place by means 
of wind. Insects as agents are rare, although one does occa- 
sionally find special adaptations intended to secure their visits. 
The spores of many fungi are forcibly ejected from the sporo- 
carps, asci, or sporangia ; some of the many arrangements which 
ensure this will be given in the special part of this book, others 
will be found in the works of Zopf , 1 and De Bary . 2 Ludwig, 
in his text-book , 3 points out that the spores of many Ustila- 
gineae frequenting entomophilous flowers, are provided with 
ridges and spines, which are probably an adaptation to their 
transportation by insects; smooth-coated spores are more common 
on leaves, stems, and organs other than the flower, and are 
evidently distributed by the agency of wind. 

The mode of distribution and infection is quite apparent in 
many fungi. Thus in the oat-smut ( Ustilago avcvae), the 
diseased ears in a field rise above the sound, so that the light 
dusty spores are shaken out in clouds by the slightest wind ; 
they hibernate on the earth or on straw, and germinate in 
spring to infect the oat-seedlings at the base of the stem. 
Equally simple is the distribution of spores and conidia from 
one plant to another by wind during summer. Good examples 
of this mode are the conidia of the Erysipheae, and the 
aecidiospores and uredospores of the Uredineae. Thus, the 
yellow spores of Chrysoviy.ro rhododcndri, when the aecidia are 
present in very large numbers on the needles of spruce, 
may cause the phenomenon known as “sulphur-rain.” It is 
well known that this is generally due to the yellow pollen of 
conifers caught and carried to the ground in showers of rain, 
but R. Hartig describes a case observed by him near Achen-see 
(Tyrol), where objects were covered by a yellow dust, consisting 
exclusively of spores of Chrysomyxa. Spores of this kind are 
capable of transport to very great distances, so that heteroecious 
species can still keep up their connection even though by no 
means near each other. 

Aecidiospores of all kinds are distributed more by wind than 
by insects. In rare cases, however, the aecidia have a sweet floral 

'Zopf, Die Pi/ze, 1890, p. 349. 

2 De Bary, Morphology and Biology of the Fune/i, English Edition, 1SS7. 

* Lehrhuch d. niederen Kryplogatnen, e.g. p. 370. 


NATURAL AND ARTIFICIAL INFECTION. 


55 


odour, e.y. Aec. odoratum in America. The wind we must also 
regard as the distributor of uredospores and of the sporidia of 
germinating teleutospores. The Uredineae have typical spores 
for distribution by wind with the exception of the so-called 
spermogonia. These structures are produced by most Uredineae, 
generally on the upper surface of the leaf and before the aecidia; 
they are brightly coloured, and give out sperrnatia in a sticky 
gelatinous slime, frequently with a distinct odour. Thus they 
seem to be admirably adapted to transport by insects, and are 
in fact visited by them. Their distribution, however, has little 
importance, since they are, as far as known, incapable of 
germination. They are regarded by many as degenerate forms, 
either of male sexual organs, or of pvcnidia. Some of the 
sperrnatia have been made to germinate in artificial culture, 
but of their incapacity to germinate in natural surroundings 
there can be no doubt. I am not aware of any one who 
has succeeded in bringing about infection with these sperrnatia, 
but I have tried it often with no result. 

It is much more difficult to ascertain how fungi, which 
hibernate on the earth, find their way in spring to their 
respective host-plants, in some cases even to the crown of very 
large trees. Amongst such forms one frequently finds an 
arrangement by which the spores are forcibly ejaculated. Thus 
Ehytisma acerinum, which reaches maturity only in spring after 
hibernating on dead sycamore leaves, and Sclerotinia letulae, 
which does so on fallen fruits of birch, both have their spores 
forcibly ejaculated and carried off by wind. Klebahn states 
that the ejaculation takes place in dry weather, and that the 
spores of Eliytisma are prevented from drying up by a gela- 
tinous covering. In a similar manner the hibernating spores of 
Erysipheae on fallen leaves must be carried up again by wind ; 
so also those of Folystigma, which ripen on the ground and then 
infect young leaves of plum and cherry trees. 

Infection by means of the mycelium generally occurs where 
the mycelium lives in the earth. Thus, the hyphae of Trametes 
radiciperda grow rapidly from one root to another, causing a 
centrifugal spreading of the fungus, so that forests attacked by 
it have the trees killed off in patches. Mycelial infection is still 
more effective in fungi like Ayaricus melleus which assume the 
form of rhizomorphs. Infection by means of the mycelium may 


56 


NATURAL AND ARTIFICIAL INFECTION. 


also occur amongst species of fungi living above ground. Thus 
the mycelium of Botrytis spreads from plant to plant, and on seed- 
lings in hot-beds, may form felted masses. Similarly the mycelia 
of Erysipheae, of Trichosphaeria, and of Herpotrichia make their 
way from one part of a plant to a neighbouring part in contact. 

Artificial infection may be carried out by means of spores 
or by mycelium. In the case of swarm-spores, the operation 
can oidy be conducted in a damp chamber and on well- 
moistened leaves. Thus, young plants of beech must be well 
sprayed, then infected with conidia of Phytophthora omnivora, 
and placed under a bell-jar to prevent drying up. In this and 
many other similar cases one finds that while the spores require 
moisture to ensure germination, yet the germ-tubes easily leave 
the water-drops and penetrate into the leaves ; in other words, 
the living leaf exerts a greater infiuence on them than the water, 
the chemotropic stimulus is stronger than the hydrotropic. 

The spores of the lower fungi are best isolated by the aid 
of a lens or microscope, then washed on to the place to be 
infected. In the case of Ustilagineae and Uredineae the same 
method is used, except that dry powdery forms of spore are 
simply dusted on to the host-plant to be infected. When spores 
of Ustilagineae are being used the addition of excrement of 
some sort is frequently of advantage, since it promotes better 
germination and the formation of conidia capable of infection 
after it is exhausted. One must also pay attention to the fact 
that some smut-spores can only infect the base of the stem or 
parts in process of elongation, while others can only attack 
parts of the flowers. The teleutospores of the Uredineae must 
first be germinated in order to obtain the sporidia with which 
infection is carried out ; this generally takes place in water. 
Thus with species of Gymiiosporangium it will be found best to 
mix the whole gelatinous mass of teleutospores with a little 
water in a shallow glass dish, and to ascertain, by microscopic 
investigation after a few hours, whether any sporidia have been 
produced. If this be the case, the gelatinous mass is thoroughly 
broken up, more water added, and the yellowish water sprinkled 
over the host-plant. Care must, however, be taken that the 
larger portions of the teleutospore-mass are not left on the 
leaves, otherwise death of the latter will occur at these places 
without infection taking place. For a similar reason it is not 


NATURAL AND ARTIFICIAL INFECTION. 


57 


advisable to lay portions of diseased leaves directly on healthy 
ones, it is much better to place them near each other in a 
moist chamber, hanging the former over the latter. 

When infection is carried on out-of-doors, it is best to obtain 
a small plant which can be accommodated under a bell-jar. If 
this be unattainable, it is often possible to bend one of the lower 
branches down to the ground or other support, so that it can be 
covered with a bell-jar. Again, a branch or portion of it may be 
first sprinkled, then bound loosely up in a parchment-paper. 
When carrying on infection it is of importance to avoid very 
hot and dry or cold days ; moist, warm and cloudy days, or close 
still nights, will be found best. In the case of diseases of the 
rind, it is generally necessary to wound the periderm by a few 
fine knife-cuts, then to place thereon a few drops of water with 
infecting spores suspended in it. 

Artificial infection by means of mycelium is generally 
attained by placing a diseased portion containing living my- 
celium in contact with the healthy, so that the mycelium can 
grow from the one to the other. Thus, with bark-diseases, a 
small portion of diseased rind is cut out and fitted into a 
corresponding incision in the rind of the plant to be infected, 
the oculation or graft being then protected against drying up by 
gutta-percha, tree-wax, or parchment. The ingrafted portion 
need not fit very accurately if well bound up, because the 
mycelium will grow well in the moist chamber so formed. The 
most vigorous mycelium is generally found on the boundary be- 
tween healthy and diseased parts, so that portions from this 
region should be selected for infection. 

If the fungus under investigation frequents the wood, it is, as 
a rule, a wound-parasite, so that for its infection the wood must 
be laid bare, and a diseased portion applied to it. If a branch is 
to be infected ( e.g . with Nectria, or Cucurbitaria), then it should 
be cut over a bud, the exposed end split, and a fine wedge of 
diseased wood inserted, the whole being bound up. It is also 
possible to graft a diseased branch on to a healthy. In the 
case of stems, a portion of the healthy one should be removed, a 
diseased piece inserted, and the wound closed over with grafting- 
wax or clay. Pressler’s growth-borer may in such cases be 
used with good results to obtain a cylinder of diseased wood, 
and to make a suitable receptacle for it in the sound plant. 


CHAPTER V. 


DISPOSITION OF PLANTS TO DISEASE. 

§11. We must here distinguish between an internal or 
inherent disposition dependent on the constitution of the living 
protoplasm of the host-cells, and an external or accidental dis- 
position arising from anatomical peculiarities or from the con- 
ditions ofkmivironment. 

The conditimi of inherent disposition has as yet been little 
investigated. $1 many cases it must be allowed that resting 
cells are more' disposed to disease than those in full activity 
of life. Thus J)e Bary, 1 basing his conclusions on the observations 
of Davaine and Brefeld, points out that various species of Mucor, 
Prnicilliurn, and allied forms penetrate into ripe juicy fruits, 
and remarks : “ Observation of the fruits shows that the fungi 
develop more easily, the nearer the vital powers of the plants 
attacked k re to their lower limit, and at this point the conditions 
of saprophytic vegetation make their appearance.” 2 Davaine 
also foinid that the vegetative organs of several succulent plants 
show t lie same phenomena as the fruits. As further examples 
may lie mentioned that fungi can frequently penetrate withering 
plant-organs while they could not infect the fresh living tissue. 
Hartig observed on Peziza Willkoinmii that the mycelium of this 
bark-parasite advanced and killed the tissues only while the host- 
cells were in a condition of vegetative rest, not during their 
active period. 

1 Morphology and Biology of the Fungi, English Edition, p. 3S0. 

3 Wehmer (Beit rage z. Kennt. einheimittcher Pilze, Jenn, 1S95), 1ms contributed 
new facts to this subject, which are referred to later. 


DISPOSITION OF PLANTS TO DISEASE. 


59 


Hartig 1 also found that Agaricus mellev.s, in penetrating into 
stools of oak, only killed those cells which, as it were, rested, 
whereas the cells of parts in communication with stool-shoots 
are not attacked. Likewise, Schwarz states that the mycelium 
of Cencingium abietis only extends through pine-shoots at a time 
when there is little vegetative activity. 

Accidental disposition depends largely on the nature of the 
epidermis enclosing plant-organs. The stems of many plants are 
protected from intruding fungi from the time the epidermis is 
replaced by a corky layer, still better after a bark is formed. 
Hence young shoots are in a condition of greater disposition 
than older ones. There are, however, various grades of dis- 
position to be observed, even when a simple epidermis forms 
the only covering, as is the case with most leaves, bowers, and 
many fruits. The newly-formed epidermis is, as a rule, most 
disposed while its walls are still delicate and uncuticularized, 
hence many organs are exposed to attacks of fungi only in their 
youngest condition. It is easy to infect and kill young leaves, 
and shoots of conifers with Botrytis Bovglasii, whereas older 
needles will remain quite unharmed. Similarly with Chrysomyxa 
rhododendri on spruce-needles, Calyptospora Goeppertiana on 
silver hr, and others. Flowers are also more easily infected 
in the young stage, c.g. cones of spruce by Aecidhnn strobilinvm. 

During early youth plants are insufficiently protected from 
great cold and drought, and also from infection by parasitic 
fungi. This may be because the young non-cuticularized walls 
offer less resistance to the germ-tubes and haustoria,.; or because 
they are more peimeable to any feiment excreted by the fungus. 
Organs developed late in the vegetative season resemble those 
in the spring-condition in that they have not as yet matured, 
and are hut poorly protected against extremes of temperature, 
or attacks of parasites. 

The condition of disposition may be easily promoted for 
purposes of artihcial infection, by cultivating the host-plants in 
a moist chamber, or under a bell-jar. The same condition 
may easily arise in glass houses or hot-beds, hence one has, by 
means of constant ventilation, to guard against it. 

Many diseases of seedlings ( e.g . Pluytoplithora omnivora, 

and Pythium ) are only to be feared so long as the stems of 
1 Forstl.-naturwiss. Zeitsehrift, 1894 . 


60 


DISPOSITION OF PLANTS TO DISEASE. 


their hosts are unprotected by cork-formation. Plant-organs 
rich in water are in a condition which disposes them to attack, 
much more than drier parts. The younger parts of any plant 
are more disposed than older parts. Thus in a spruce-hedge 
with young shoots appearing at different times, only those 
shoots will be liable to attack, which are young at the time 
of the scattering of the spores of Chrysomyxa abietis, or other 
spruce-fungus. De Bary was of opinion that plants of Capsella 
were disposed to attacks of Cyst<ypus candidns, only as long as 
they retained their cotyledons, because only those spores ger- 
minating on the cotyledons form a mycelium which ultimately 
finds its way through the plant, whereas plants which had 
already lost their cotyledons at the time of infection were 
in no danger. Many of the Ustilagineae attack cereals only 
when these have just emerged from the soil, infecting the 
young stems on the first sheath-leaf, whereas older and more 
advanced individuals are exempt. While all plants with a 
delicate epidermis or corky layer are liable to disease, yet some 
are more so than others. This is exemplified by the different, 
powers of resistance to disease, or insect attacks exhibited by 
nearly allied forms of our cultivated plants, e.y. vines ; a differ- 
ence probably due to some variation in their outer membranes, 
such as is further demonstrated by thick-skinned potatoes being 
more resistant to disease than thin-skinned. 

Disposition is often due to external circumstances. These, 
however, act rather in presenting favourable opportunities for 
infection by germinating spores, than by directly disposing the 
plant to disease. Thus prolonged wetting of a leaf from rain 
favours germination of spores, and at the same time by softening 
the leaf, facilitates penetration of the germ-tubes. Stahl 1 has 
pointed out that leaves on which water remains for any length 
of time, present greater opportunity for growth of saprophytic 
epiphytes or for infection by parasites, than leaves with a 
smooth surface or of a shape which facilitates ready escape of 
water from their surface. It is also well known that larches 
in damp situations suffer more from Pcziza Willkommii than 
those in drier places, the fungus-spores maturing and germinat- 
ing only in moist air. Similarly, moist weather or damp 

1 “ Regeufall u. Blattgestalt,’ - Ann. du Jardin botan. de Buitenzonj, XI., 1893, 
I). 124. 


DISPOSITION OF PLANTS TO DISEASE. 


61 


situations favour reproduction of mildew and other diseases ; 
under such conditions a rapid increase of potato-disease during 
July is easily observable and may be safely foretold. 

The extension of Hcrpotrichia is greatly facilitated by snow, 
which weighs down young plants or branches of spruce and 
pins them to the soil, where the fungus develops on its host 
under the snow-covering. On this account elevated situations 
and hole-planting render the spruce liable to disease. 

Many plants which, as a rule, suffer from fungus-diseases 
will be found to remain exempt in open or dry situations, or 
during a dry period. The tops of trees are not attacked by 
many fungi which frequent the lower parts of the crown. This 
is particularly the case with epiphytic lichens and certain fungi, 
which require a high degree of air-moisture. Trichosphaeria 
parasitica, always very abundant in damp silver fir regenerations, 
is almost absent from free-standing trees, or from the higher 
parts of the crown in closed forest. It is, in fact, a parasite 
well adapted for extension in the crowded masses natural to 
the early growth of the fir, and the host is, during its youth, 
disposed to disease from this particular parasite. A fungus on 
the beech behaves similarly, occurring in Bavaria only in the 
very damp parts of close high forest and in Alpine gorges. 
Other fungi have better means of protection against drought, 
for example, Hysterium mcicrosporium has its spores enclosed in 
gelatinous envelopes and may be found on the highest point of 
the spruce, although, on the whole, its distribution is most 
favoured by moisture. Fungi which frequent algae, or are dis- 
tributed by means of zoospores, depend absolutely on moisture ; 
hence they frequent hosts growing on banks of streams, places 
liable to flooding, or low-lying moist meadows, whereas the same 
host-species remains completely exempt from their attacks in a 
dry locality. 

A plant may be said to be in a condition of abnormal 
disposition to disease when deprived of its natural protection. 
Thus wounds of any kind render a plant disposed to infection 
from wound-parasites, which are unable to harm uninjured parts. 
After severe hail-storms an outbreak of Ncctria ditissimcc is not 
unfrequent amongst regenerated beech, or even in the canopy 
of older forest. I have also observed an extensive outbreak of 
Cucurbitaria laburni on laburnum near Munich, obviously due 


62 


DISPOSITION OF PLANTS TO DISEASE. 


to hail. Juicy fruits whose epidermis has become broken, soon 
rot unless a protecting layer of wound-cork is rapidly formed. 
Wounds in the wood present an entrance-gate to numerous 
Polyporeae, otherwise unable to penetrate. In the case of 
wounds to the wood of spruce or young branches of pine, a 
protecting crust is frequently formed by the rapid excretion 
of resin from the injured surface . 1 

The disposition of a host-plant depends then on some inherent 
condition of the protoplasm or on some accidental circumstance. 
The latter may be anatomical and due, for example, to thickness 
or other property of the cuticle, or to a hair-covering ; it may 
be morphological, from some defect, say on the part of the leaf 
in not allowing easy escape of water. The disposition may be 
periodic ( e.y . in youth or at llowering), or it may be permanent. 
It may be generic, or confined to some particular variety or 
species, or it may be individual. It may be normal or abnormal. 

The practical lesson of this chapter has been that we should 
cultivate our plants so as to avoid the conditions which dis- 
pose them to disease, and that we should rear and cultivate 
these kinds least liable to injury from disease. The considera- 
tion of these points forms the subject of our next chapter. 

1 Resin is in itself not antiseptic, and in the fluid condition inside plants 
affords no harrier to fungus-hyphae of Peridertniutn jiini and N'ectria cucurbitu/a ; 
the hardened crust on a wounded surface serves, however, to keep off spores 
from the plant tissues, and prevents the penetration of germ-tubes. 


CHAPTER VI. 

PREVENTIVE AND COMBATIVE MEASURES. 

§ 12. Measures are known for the prevention and cure of many 
fungoid diseases of plants of agricultural, sylvicultural or horti- 
cultural interest. These have been deduced from the biology of 
the parasite and its relation to its host, and have been used 
practically with more or less success. In a large number of 
cases, however, little advice can be given, because as yet the 

cause of many diseases is obscure, while for others suitable 

reagents for cure have not been found. Many of the methods 
known are impracticable from the cost entailed in carrying 
them out. Others, directed against some widespread disease, 

fail from lack of organized co-operation, the efforts of a few 
individual cultivators here and there making but little headway 
against the disease, so long as the patches of crop under treat- 
ment are subject to fresh invasion from untreated places. It is 
desirable on this account that the combating of diseases of our 
cultivated plants should be conducted under some kind of state 
supervision. 

The first step towards combating the more destructive diseases 
of plants is the spread of knowledge concerning them, and the 
remedies available against them. In Bavaria and other German 
states this is done for the diseases of sylvicultural importance by 
regular courses of instruction in plant-pathology in the forestry 
schools. In the same way it would also be advisable to give 
similar instruction in agricultural schools, and also to make it a 
subject for examination. Another important step consists in the 
establishment of experimental stations where investigations in 


04 


PREVENTIVE AND COMBATIVE MEASURES. 


plant-pathology may be carried out, while at the same time the 
cultivator could have advice with regard to the nature of any 
disease and its treatment. Another system for the supply of 
information is to be found in collections of specimens of plant- 
diseases arranged for easy reference in places accessible to the 
public. 

State supervision over crops under cultivation is also desirable 
with a view to collect and distribute information concerning 
prevalent crop-diseases. The same agency could also arrange 
and, if need be, enforce a general and simultaneous treatment of 
widespread epidemics, where proved methods were known and 
advisable. Such regulations for supervising and combating a 
plant-disease are already universally applied against the Phyl- 
loxera. Similarly in Germany and other countries official 
notice is annually given for extermination of mistletoe ( Viscum 
album) on fruit-trees, and in Prussia the combating of Gnomonia 
erytlirostoma is carried out by order of the police authorities. 
The tar-ringing of trees as a preventive against attacks of pine 
moth (Gastropacha pini), is regularly enforced everywhere in 
forest-countries, and with the best result. In a similar manner, 
in most countries, this and other forest pests are supervised by 
the penal code, and combated with success. 

By arrangements of this kind it is possible to keep certain 
diseases completely in check. Thus, as a result of regular in- 
spection and the timely use of tar-rings, a dangerous outbreak of 
pine moth is well-nigh impossible. Again, the universal steriliza- 
tion of the seed-corn of cereals before sowing has done much to 
exterminate smut-diseases. In the case of the Dodder-disease, 
much can be done for its prevention by the careful purification 
of clover seed. 

We shall consider the methods for combating parasitic fungi 
under the following heads : 

I. Methods for extermination and removal of the parasitic 
fungi alone. 

(1) Killing of fungi attached to seed through sterilization by 
means of hot water or copper steep-mixtures. 

(2) Combating leaf-frequenting fungi by dusting or spraying 
with mixtures containing sulphur or copper. 

(3) Excision and extermination of the sporophores of I’olyporeae 
and Agaricini on orchard or garden trees. 


PREVENTIVE AND COMBATIVE MEASURES. 


65 


(4) Eemoval and destruction of dead parts of plants carrying 
sporocarps or other hibernating stages of any fungus. 

II. Methods for combating fungi by removal of diseased 
plants or plant-organs. 

(1) Eemoval of the parts of a host-plant harbouring fungi. 

(2) Eemoval of the whole or part of a complementary host 
of a heteroecious fungus, for the purpose of saving the other 
host or hosts. 

III. The avoidance or removal of conditions which favour 
infection. 

(1) Preventive measures against wound infection; antiseptic 
and aseptic wound-treatment. 

(2) Avoidance of localities favourable to disease. 

(3) Avoidance of the massing together of plants of the same 
species and like age ; rotation of crops on the same cultivated 
area. 

(4) Avoidance of neighbourhood of those plants which are 
hosts of the same heteroecious fungus. 

IV. Selection and cultivation of varieties and species of 
cultivated plants least liable to the attacks of parasites. 

I. Extermination and removal of the parasitic fungi alone. 

(1) That the seed be clean and free from the spores of 
parasitic fungi, is a most essential condition. The purity of 
seed is investigated in seed-control stations, 1 where special 
attention is paid to purity of seeds ( c.g . clover, from its 
liability to contain seeds of the parasitic Dodder), and to their 
freedom from spores of smut or other fungi. 

As a preventive against smut, especially those forms due 
to species of Ustilagineae, sterilization of the seed is adopted, 2 
This is chiefly carried out by the use of “ steeps,” which kill 
the smut-spores adherent to the seed. The composition of the 
steep-liquid, and the duration of immersion are the points to be 
attended to, and for these various recipes are extant. Eecently 

1 State-aided stations of this kind are fairly numerous in Germany, France, 
and other continental countries, also in America. It is thus somewhat remark- 
able that in Britain this important work receives no state recognition, but is 
left in the hands of more or less experienced analysts, or others. (Edit.) 

2 Swingle, W. F. “Grain-smuts and their prevention.” Yearbook of 
U.S. Dept, of Agriculture, 1894. A very useful summary. (Edit.) 

E 


66 


PREVENTIVE AND COMBATIVE MEASURES. 


it has been pointed out that the different species of Ustilago 
have different powers of resistance, and must be treated 
accordingly. It has been found from experience that when 
trustworthy and tested steeps are in general use in any neigh- 
bourhood, the diseases of crops caused by Ustilagineae gradually 
disappear. This is due to the fact that the smut-fungi frequent 
principally the cultivated cereals, while they are comparatively 
rare on the wild grasses from which, as in the case of “ rusts,” 
they might make their way to the cultivated forms. 

Sterilization by Copper Sulphate. 

The “ steep ” which is in most general use is that first recom- 
mended by Kiihn 1 in 1858. It consists of a | per cent 
solution of copper sulphate prepared as follows : 1 lb. crushed 
commercial sulphate of copper (blue vitriol or bluestone) is 
dissolved in hot water and added to 22 gallons of water. The 
seed is poured into the “ steep ” and allowed to stand covered 
with the liquid for a night (twelve to sixteen hours). The 
seed is then taken out and allowed to drip. An improvement 
on this method consists in running off the copper sulphate 
liquor and adding milk of lime (prepared by soaking 1 lb. 
good lime in 4 gallons of water), after stirring for about five 
minutes, again run off the liquor and allow the grain to drip. 

If sown by hand the seed may be used in a few hours, if 
by machine it must dry for twenty-four hours. 

Sterilization by Hot Water. 

.Jensen’s method for treatment of seed-grain by hot water, 
consists in placing the seed for a certain time in water at a 
temperature which does not injure the grain, but is sufficient to 
kill any adherent smut-spores. This takes place in five minutes 
in water at 132° F. (55 C.), but the germinating power of 
the grain will not be injured though it remains a quarter of 
an hour. The immersion is carried out by placing the seed in 
a vessel easily permeable by water ; a bushel basket lined with 
coarse canvas serves very well. A convenient quantity of seed 

‘Julius Kuhn, Die Krankheiten d. K uUunje u'dchse , ISAS, p. SO. Numerous 
articles on t>his subject have from time to time appeared in the agricultural 
Journals and Bulletins. 


PREVENTIVE AND COMBATIVE MEASURES. 


G7 


to handle in such a basket would be a full half-bushel. The 
hot water is best contained in two large boilers, the first at a 
moderate temperature, serving to wet the grain somewhat and 
to prevent cooling of the water of the second boiler, which 
must be maintained between 130° F. to 134° F. A lower 
temperature will not ensure death of all spores, a higher will 
injure the grain. The grain is immersed a few minutes in the 
first boiler, then placed in the second for fifteen minutes, being 
meanwhile frequently shaken to ensure complete sterilization. 
Next the basket and its contents are cooled in cold water and 
the grain spread out to dry. 1 

The important point in the application of these methods is 
their general and simultaneous use throughout a whole district. 

For smut-diseases the removal of diseased plants is at the 
same time a preventive and a combative measure. This is 
not difficult where the plant is large or the disease conspicuous, 
as with the maize-smut ; the diseased plants can then be re- 
moved and burnt before the smut-spores are shed. If the smut 
is not very prevalent it is possible to keep it in check by 
removal of diseased specimens on such crops as maize, barley, 
wheat, and oats. This treatment can also be applied to some 
garden-smuts like that on violets. 

Brefeld recommends as a preventive measure the avoidance 
of the use of fresh farmyard manure. Smut-spores from in- 
fected hay or straw, which finds its way to the manure heap, 
germinate there and multiply yeast-like giving rise to conidia, 
which, on exhaustion of nutrition, give rise to germ-tubes 
capable of infecting seedling plants. The spores are capable of 
germination even after being eaten with the fodder and passing 
through the digestive canal of animals. In this connection 
Professor Wollny carried out the following experiment at my 
instigation : three fields situated at some distance from each 
other were sown with maize, which I had mixed with living 
spores of Ustilago maydis collected the previous autumn. One 
field was left unmanured, the second received old farmyard 
manure, the third fresh. All plants in the first plot grew up 
healthy, two of the second were diseased, and eleven of the 
third. The summer being a dry one the number of diseased 

1 In the literature issued from the United States Experimental Stations 
other “steeps” are given, with results. (Edit.) 


68 


PREVENTIVE AND COMBATIVE MEASURES. 


plants was smaller than usual. The immunity from smut with 
old manure is probably explicable on the assumption that in 
it the kind of nutriment suitable for the smut-conidia is ex- 
hausted, so that any spores, which may sprout, die off. 

It must, however, be here observed that the spores of some 
species of smut-fungi ( c.g . Tilletia, the stinking brand of wheat) 
do not germinate directly in manure, but do so in water easily. 
The spores of most smuts are adapted to a long winter rest. 

(2) Other diseases are fought and prevented from spreading 
by the direct extermination of the fungus or its reproductive 
organs while in full activity on the growing host-plant. For 
this purpose Fungicides are used, either as powders or solutions 
applied to diseased plants. These reagents are employed with 
most success against epiphytic fungi, where the mycelium is 
fully exposed on the surface of the host. 

The Erysipheae are generally treated in this manner, especially 
the powdery mildew of the vine ( Oidium Tuclceri or Uncinvla 
spiralis). This vine-parasite is combated by dusting from time 
to time with dry powdered sulphur or Howers of sulphur. The 
sulphur may be simply shaken from a tin with perforated lid, 
or it may lie blown on by a sprayer provided with a bellows, 
or dusted on by a sulphur-brush, consisting of a hollow handle 
filled with sulphur which distributes the powder through fine 
perforations in its end to a tassel of fine bristles. In a similar 
manner may be treated the powdery mildews of hop, rose, 
peach, apricot, apples, etc., caused by Erysipheae. 

Fungicides are also used against fungi with endophytic 
mycelia. The Peronosporeae cause injury to quite a large 
number of cultivated plants, and many methods of treatment 
have been employed against them. The mycelium lives inside 
the host-plant, especially in its leaves, and only the conidiophores 
make their appearance externally. Dusting with sulphur or 
spraying with preparations of copper has on this account little 
efiect on the mycelium, but will kill the conidiophores, while 
any conidia or oospores, which may alight on the leaves, will 
be prevented from germinating. The most general forms of 
fungicides are various preparations of copper, of which the 
following are some of the more important : 1 

’Considerable liberty has been taken here with the original. The authors 
account has been extended with the assistance of the Journal oj Mycoloyy and 


PREVENTIVE AND COMBATIVE MEASURES. 


69 


Bordeaux Mixture or Bouillie-Bordelaise, a 2 to 4 per cent, 
solution of copper sulphate and lime. It is prepared by dis- 
solving 6 lbs. of copper sulphate in warm water, and placing 
this mixture in a barrel capable of holding about 44 gallons ; 
in another vessel slake 4 lbs. of fresh- burnt lime, and make it 
up to a creamy whitewash with water ; strain the lime through 
coarse canvas into the barrel of copper sulphate solution, fill 
up with water, stir thoroughly, and the mixture is ready for 
use. This mixture may be used either more concentrated, or 
somewhat diluted. 

Ammoniacal Solution of Copper Carbonate. This may be 
prepared directly by dissolving 5 oz. of copper carbonate in 

enough water to form a thick paste ; dissolve this paste in 

three pints of strong aqua ammonia (or as much as may be 
necessary to effect complete solution) then dilute to 45 gallons. 
If copper carbonate cannot be obtained, make it by mixing (a) 
3 lbs. of copper sulphate in 2 gallons of hot water, ( b ) 34 lbs. 
washing soda in 1 gallon hot water ; mix («) and ( b ), add 

water up to 10 gallons, stir up, and allow to settle; pour off 
the clear liquid, fill up again with water and allow to settle ; 
on again pouring off the clear water a greenish sediment of 

copper carbonate remains. This dissolved in as much aqua 
ammonia as necessary, may be kept till required when it is to 
be diluted at the rate of 1 pint to 2 gallons of water. 

Eau Celeste. Dissolve 2 lbs. of copper sulphate in about 
8 gallons of water ; when completely dissolved add 3 pints of 
strong aqua ammonia and dilute to 45 gallons. This may be 
used in a modified form. 

Fungicides like these are used chiefly against attacks of vine 
mildew ( Peronospora viticola), potato disease ( Phytophthora in- 
festans ) and Peronosporeae generally ; also for numerous other 
leaf-diseases caused by various fungi. What the results of any 
given experiment may be, is as yet difficult to say till more is 
known of the effects of the reagents, the strength of the mix- 
ture to be used, the kind of plant and its stage of development, 
and other factors dependent on climate. The efficacy of a 
fungicide lies less in its effects on the fungi actually present 

other American literature, not the least important being “ Bordeaux Mixture as 
a Fungicide,” by D. C. Fairchild ; U.S. Amer. Bulletin, No. 6, 1894. In this 
connection reference may also be made to E. G. Lodemann’s account of the 
“Spraying of Plants” (Macmillan, 1896). (Edit.) 


70 


PREVENTIVE AND COMBATIVE MEASURES. 


and causing disease, than on its capacity to kill spores which 
light on the leaf, or to prevent their development to a dangerous 
extent. On this account crops liable to attack should be dusted 
or sprayed in early spring, and at intervals thereafter as long 
as there is any risk of disease. Used in this way, fungicides 
soon repay themselves in increased yield of healthy produce ; 
on the one hand, they hinder the development of the fungus, 
on the other hand, they act like antiseptic wound-treatment in 
preventing infection. What part the copper compounds play 
is as yet not completely established ; Rumin 1 considers that 
they are not actually absorbed by the plant, but only give rise 
to some electrical effect. 

The advantage to be gained from the use of fungicides may 
be greatly increased if all diseased plants or portions of them 
be removed before the remedy is applied. Precautions must 
also be taken against reappearance of the disease. In the case 
of infected forcing boxes, frames, or glass-houses, disinfection 
by some of the above fungicides is certainly advisable. Leaves 
on other plant-remains containing resting-spores of the fungus 
should be burnt, and soil containing diseased material should 
be watered with a fungicidal solution which will kill the fungus 
while it does no harm to the leaves or roots of plants. Finally 
a rotation of crops of as long a duration as possible will do 
much to keep epidemic fungoid diseases in check. 

(3) Frequently the ravages of a parasite can be considerably 
reduced, although not completely stopped, by destroying its 
reproductive organs. Methods of this kind are particularly 
useful in the case of the Polyporeae which inhabit the wood of 
many fruit-trees. The excision of the sporophores must be 
carried out once or twice a year, because the mycelium remains 
alive inside the stems and continually gives off new sporophores 
on the surface. The diseased tree lives on and produces fruit 
for many years, maybe till the wood of its stem becomes so 
much decayed that death ensues. Fungi of this family are 
even more destructive on those trees which are cultivated not 
for their fruit alone but also for timber, c.g. olive, sweet chest- 
nut, and hazel. 

(4) By the removal and destruction of dead plants or portions 
of plants containing reproductive or hibernating organs of para- 

1 C. Rumm, Berichle d. deutseh. hofan. Gts. 1S93. 


PREVENTIVE AND COMBATIVE MEASURES. 


71 


sites, much may be done to shorten the existence of a disease, 
and to prevent its reappearance in the following spring. 

Fungi which reach maturity on fallen leaves are easily com- 
bated in this way. Hartig gives a striking example of the 
success of this measure. In the English Garden, a large park 
in Munich, the leaves are carefully removed at frequent intervals 
as they fall, and utilized as stable-bedding ; here Rhytisma 
acerinum, the black spot of the sycamore leaf, is hardly known, 
whereas in the park at Nymphenburg, and in other places 
round Munich, where the leaves are allowed to remain lying, 
the leaf-spot is very common. Rhytisma salicinum can be 
treated in the same way in osier- nurseries. In plum orchards 
Polystigma rubrum may be held completely in check by removal 
of fallen leaves. So also the numerous mildews (Erysipheae) 
of our cultivated plants. Cherry leaves killed by Gnomonia 
erythrostoma remain hanging on the trees, but the disease has 
almost disappeared since the practice of removing and destroying 
these was introduced in gardens, like those of the Altenland, 
once completely devastated by this parasite. 

The progress of the disease caused by Nectria cinnabarina is 
reduced if the branches which die during the summer be at 
once removed and burnt before the red fructifying patches 
appear. It would also be advisable to burn in the autumn 
other dry brushwood, since it frequently contains Nectria and 
other wound-fungi, and if left over winter only serves as a 
nursery and source of infection for all neighbouring trees. In 
a similar way should be treated branches infected with sporo- 
carps of Cucurbitaria laburni and such-like fungi. 

Immediate removal, burning, or burying of young trees 
attacked by Phytophthora omnivora is of advantage in prevent- 
ing the distribution of the fungus by conidia and swarm-spores 
during summer, its hibernation in dead tissues, and its continued 
distribution in the following spring. The hibernating oospores 
of many other lower fungi may be similarly got rid of by 
destruction of the plant-remains inhabited by them. 


II. Removal and destruction of diseased plants or portions of these. 

(1) The removal of symbiotic organs comes here particularly 
into notice. Amongst these are the “ witches’ brooms ” which 


72 


PREVENTIVE AND COMBATIVE MEASURES. 


live for years on their host deriving nutriment from them ; 
they also are detrimental to fruit trees because they bear 
neither flower or fruit, and on some timber trees they so 
deform the stems as to considerably reduce their value. The 
witches’ brooms of the cherry or the plum grow into large 
infertile bushes of striking appearance, so that they may be 
easily detected and removed in autumn or spring ; those on 
hornbeam, birch, and alder are of less practical importance, 
but should be cut off wherever accessible. 

Great damage is caused by the witches’ broom (Aecidium 
elatinum ) of the silver fir in producing canker spots which 
may in some cases attain gigantic dimensions and thereby 
much reduce the value of the timber, or maybe render it quite 
valueless. The cankered spots are, in addition, frequently attacked 
by wound-parasites, whereby the stem is weakened and breaks 
over at the canker, causing breaches in high forest, which can- 
not be refilled. The witches’ brooms should therefore, as far as 
accessible, be cut off while still young, and all cankered trees 
should be removed at the first thinning. 

The removal of twigs of plum bearing the so-called “ pocket- 
plums ” or “ fools ” is also to be recommended, because the my- 
celium of the fungi causing these hibernates in them. Rose-twigs 
affected by rose-mildew ( Sphacrothcca pannosa) should also be cut 
away as soon as possible, before many plants have fallen victims. 
Portions thus removed are both worthless and dangerous, hence 
should be destroyed. So also all trees rotted by fungi should 
be removed from their healthy neighbours, and, if possible, 
burnt or buried, or otherwise rendered harmless. 

This forms a convenient place to consider generally the 
wood-destroying wound-parasites of our timber-producing 
plants. 

The wood-destroying wound-parasites belong chiefly to the 
families of the Polyporeae and Agaricini, and each possesses a 
mode of life and method of destroying its host, so similar to 
that of its relatives, that it is quite impossible to consider them 
separately in a practical way. They are enemies of our fruit 
orchards, our parks, and our forests, and the means to be em- 
ployed against them varies in the hands of the fruit-grower, the 
gardener, or the forester. 

Every fruit-tree, whether grown in a garden, an orchard, or 


PREVENTIVE AND COMBATIVE MEASURES. 


73 


on a roadside as in some countries, is an object of such value 
that, if need be, costly methods can be employed on its behalf. 
Its branches must be kept free of all intruders like the 
mistletoe, witches’ brooms, mosses and lichens, and above all, 
from the sporophores which indicate the presence of a wood- 
destroying fungus. This is all the more easy because the trees 
are frequently closely examined for pruning, for crop, or for 
insect attacks. The sporophores of fungi on stems and branches 
should, as already indicated, be early and carefully cut out, the 
wound scraped and tarred over . 1 In this way the fungus will 
be deprived of its sporophores and the safety of other trees 
ensured, although it must be remembered that the mycelium 
still continues to destroy the wood and probably to produce 
new sporophores. If the sporophores appear on weak branches, 
these would best be completely cut off and the cut end tarred 
over. Trees although diseased and requiring annually to have 
sporophores cut out should still be spared, as they often continue 
to live and yield heavily for years. Amongst the sporophores 
which appear frequently on fruit-trees are those of Polyporus 
igniarius, P. fulvus, P. hispidus, P. sulphureus, P. squamosus, 
P. spumeus, Hydnum Schiedermayri, and others to be more closely 
considered in the special part of this work. 

Particular attention of this kind is of course more difficult 
for the park-gardener, because his trees are higher and stand 
closer together. The trees are, however, of less value individually 
than fruit-trees. It is advisable, as far as possible, to keep the 
trees clean, to tar all wounds and to remove poorly developed 
branches and stems. 

To the forester in high forest all this is, however, a matter 
of difficulty. The trees are high, the forest large, and the 
individual trees of a value which does not allow of costly 
labour being expended on them. Yet there is one forest 
operation in which a plantation may at small cost be easily 
cleared of diseased stems. This is the repeated process of 
thinning, during which all diseased and backward trees should 
be felled. In forests of high value with' high-priced timber 
and near towns or centres of industry, this cleaning out is, of 
course, easy, but in remote forests with a small working staff, 

1 The sporophores cannot he removed too young ; the wounds produced should 
he treated with tar ; see Section in., p. 77. 


74 


PREVENTIVE AND COMBATIVE MEASURES. 


deficient modes of conveyance, and a small demand for the 
thinned-out material, this may appear impracticable. I shall 
give one example how the number of “ fungus-sponges ” (as 
the sporophores are called) decrease with enclosure and intro- 
duction of proper forest-management. 1 Bischoffsreut is a forest 
in Bavaria, near the Bohemian frontier, consisting of mixed 
spruce and fir up to four hundred years, and beech up to 
two hundred. Forty years ago the sporophores of Polyporus 
fomentarius, the tinder-fungus, were so numerous and large that 
for their collection for manufacture of caps, gloves, tinder, etc., 
a sum of one hundred gulden (£8 10s. Od.) was paid annually 
as rental. Ten years ago the same brought in a revenue of 
twelve shillings ; to-day it is free. In course of time the 
diseased stems have been gradually felled and less wood has 
been allowed to remain lying in the forest to decay ; as a 
result the wood-destroying fungi have now but little foothold. 
A mixed damp virgin forest is especially favourable for the life 
and distribution of fungi of this kind. 2 All fallen wood remains 
lying, while injuries from storm afford easy spots for infection. 
In Bischoffsreut eighteen per cent, of the felled heavy wood 
was at one time useless and rotten. 

(2) It is often possible to avert diseases of valuable cultivated 
plants caused by heteroecious fungi, by keeping the supplemen- 
tary host at a distance, or, if the disease has already broken 
out, to remove it altogether, with the view of keeping the 
more useful host free from the dreaded disease. 

The best example of this is presented by the heteroecious 
rust-fungus Gymnosporangium sabinae. One host frequents 
Jv.niperus sabina (savin), the other damages pear-trees, causing, 
in the case of a severe attack, considerable loss. It would thus 
be easy to exterminate pear-rust by removing the not very 
decorative savin-bush. Particularly in nurseries, it would be 
well to avoid placing pear-trees near the savin, an arrangement 
very suitable for cultivating the Gymnosporangium. 

As another example we may take Mclampsora trnmdae 
frequenting the aspen, the supplementary host of (n) Cacoma 
pinitorquum (the pine twister), and (6) Cacoma lands (larch 

1 v. Tubeuf, “ Mittheilung Ub. einige Feinde d. \V aides.” Alltg. For*t.-u . 
Jagdzeitunt/, 1887. 

- v. Tubeuf, “ Vegetationsbibler, aus <1. boehinischen Urwalde.” Oe#terrr.ich t 
Forstzeilnng, 1890, p. 108 ; with six figures. 


PREVENTIVE AND COMBATIVE MEASURES. 


75 


needle-rust). The exclusion of the aspen from the neighbour- 
hood of pine plantations is advisable as a means of limiting 
the pine-disease, and is now being recommended in forestry. 

Still another example is Puccinict graminis the rust of 
wheat and its Aecidium on the barberry. This is, in all 
probability, able to reproduce itself by means of uredospores on 
wild grasses, and to retain its position without the barberry, yet 
the latter doubtless tends to distribute the disease, and its 
removal minimises the risks of attack. 

An investigation of the heteroecious rust-fungi will easily 
furnish many examples of the same kind, and lead to the con- 
clusion that Euphorbia cyparissias, for example, should be 
exterminated near fields of peas or other Leguminosae because 
of Uromyces pisi, and U. striatus. 


III. Avoidance or removal of conditions which favour infection. 

Various examples of this have already been given when 
the conditions disposing plants to disease were under considera- 
tion in our last chapter. 

(1) The most important measures of this class are those 
directed against infection through wounds. This may be 

O o 1/ 

attained by avoiding any unnecessary wounding of woody plants, 
and the immediate treatment of any wounds rendered necessary 
in pruning or other operations. 

When the stems of woody plants are injured, the first step 
towards healing the wound proceeds from the tree itself. 
Conifers containing resin have in it a very ready agent im- 
mediately available ; the resin escapes from its ducts and soon 
hardens into a crust on exposure to air. In the case of non- 
resinous conifers and of broad-leaved trees, the first steps 
towards healing are less obvious, but it has been found that a 
healing tissue immediately begins to form on wounded surfaces. 1 
It consists of a parenchyma, the formation of which is induced 
apparently by atmospheric air penetrating into the wood, and 

1 v. Tubeuf, “ Ueber normale u. pathogene Kernbildung d. Holzpflanzen 
u. d. Behandlung v. W linden derselben, Zeitschrift f. Forst.-u. Jagd.-wesen, 1SS9. 
Contains Bibliography of allied papers. 

R. Hartig, Diseases of Trees , English Edition, 1894. 

Gaunersdorfer, Sitzungsber. d. k. A Lad. d. Wissenschaft, Vienna, 1881. 

Boehm, “ Ueber die Function d. veget. Gefasse,” Botan. Zeitung, 1879. 


76 


PREVENTIVE AND COMBATIVE MEASURES. 


its object probably is to restore the same condition of gaseous 
pressure inside the tree as existed previous to the injury. A 
number of woody plants, for example, Robinia and Quercus, 
which normally form tyloses in their heart-wood or sap-wood, 
do the same on wounded surfaces, and thereby stop up all 
the cut vessels. 1 

The formation of tyloses is due to sac-like ingrowths into the 
vessels from adjoining parenchyma, and can only take place 
where rapid growth of the closing membrane of pits or the thin 
portions of the wall of annular or spiral vessels occurs. Tyloses- 
formation takes place in normal heart-wood, and also in the 
sap-wood of many kinds of trees, except in the very youngest 
water-conducting year-rings. It also occurs in leaf-scars at the 
the time of normal defoliation. 2 Species of trees in which 
tyloses are not normally produced in the heart-wood, but in 
which the vessels of that region become tilled with resinous 
secretions, use these substances as healing agents in the case of 
leaf-fail or wounds to the wood. For these reasons it is quite 
correct to designate these preliminary steps towards wound- 
closure as a pathogenic formation of duramen, and the tissue 
derived from the process as wound-duramen. Similarly a corky 
tissue — wound-cork — may be formed in consequence of wounds 
to the bark or as an accompaniment of certain diseases. 1 
have repeatedly observed that the normal duramen is preyed on 
for nutriment by many wound-parasites, and also that this 
wound-duramen is not sufficient to keep out germinating spores 
of the wound-parasites. It cannot therefore be designated a 
protective wood, nor are the artificial methods of closing wounds 
so superfluous as some would have us believe. 3 

Frank says : “ The use of all such artificial means of healing wounds 
is thus only r necessary in serious cases, in which, in consequence of delay 
in the healing-process, decay would be inevitable without some septate 
agent. Smaller wounds, and ]>articularly cut surfaces of twigs or thinner 
branches, are, by the natural formation of protective wood accompanying 
every' wound of the wood, sufficiently protected for the few years the 

1 Molisch, “ Zur Kenntniss d. Thyllen,” Afoul, d. IVistenschafl, Vienna, 1SS8; 
Wider, Biolog. Cent ml Mat I, 1893. 

2 Stabv, “ Ueber Verschluss d. Blattnarben naeh Ahfall d. Blatter," Flora, 
1886. 

:l Prael, Pringnheim'ti Jahrlntch, 1888. 

Temnie, Landwirth*chaJU. Jnhrbueh , 1885. 

Frank, Die Krankheiten <1. Pflanten, 1894, p. 153. 


PREVENTIVE AND COMBATIVE MEASURES. 77 

•wound must remain open till completion of occlusion.” If we followed 
this view, then numerous wounds would be left freely open as entrances 
for wound-parasites, and serious loss would result. It is just the numerous 
smaller wounds ( e.g . those produced by hail), which are the principal places 
of infection for species of Nectria , Cucurbitaria, Hymenomycetes , etc., in 
fact, they form very convenient places whence a tree may be easily infected 
artificially. 

The following points in regard to treatment of branches may 
be conveniently summarized here. Trees in closed plantations 
are naturally stripped of their branches by these dying in con- 
sequence of deficient illumination ; they then break off, and 
the short stumps are soon occluded or grown over. During 
this process there is always a risk of infection by fungi, and 
“ snag-pruning ” 1 is employed to shorten the period of occlusion 
as much as possible. This at the same time prevents the in- 
clusion of long branch-stumps in the timber, and reduces the 
number of knots in sawn boards. Such dead snags or stumps 
are deficient in nutritive materials and very dry, so that they 
are less suited for the entrance of wound-fungi than wounds on 
the living branch. 

The usual process of forest-pruning is necessary to produce 
clean boles, to increase the illumination for undergrowth, or 
to utilize the branches so removed. In the operation, all 
branches should be cut off close to the shaft, no snags should 
be left, nor must injury be inflicted on neighbouring bark. 
The operation is best carried out in autumn or winter when 
the bark is most adherent to the wood, occlusion then begins 
with the renewal of vegetative activity in spring and is well 
advanced by the time the greatest dispersal of fungus-spores takes 
place. Infection by fungi will, however, be rendered quite 
impossible if wounds are immediately painted over with tar, or, 
in the case of smaller wounds on garden stock, with tree-wax 
these reagents, if applied in winter, will easily penetrate into the 
wood, and even replace the formation of protective , wound-wood. 
Hartig says on this subject : 2 “ tarring produces satisfactory 
results only when pruning has been done in late autumn or 
in winter, because it is only then that the tar is absorbed by 
the surface of the wound. It would appear that the absorption 
of tar is due partly to the diminished amount of water in the 

1 Trockenastung. 2 Hartig, Diseases of Trees. English Edit. p. 258-59. 


78 


PREVENTIVE AND COMBATIVE MEASURES. 


wood during autumn, and partly to the consequent negative 
pressure of air in the tree. When pruning is undertaken in 
spring or summer the tar altogether fails to enter the wood, 
and the thin superficial layer does not prevent the cut surface 
from drying later and forming fissures into which water and 
fungi may enter.” From what has been said it follows that 
dicotyledonous trees may be best pruned in the months of 
October, November, and December — perhaps also in January 
and February, — and that a good coat of coal-tar should be at 
once applied to the wounds. 

Conifers should also be pruned in autumn and winter, for 
although the wounds resulting from removal of small branches 
with no heart-wood are soon protected by an excretion of resin, 
yet thicker branches with heart-wood, which secretes no resin, 
must be tarred over. Similar precautions are advisable to 
protect the stools of trees felled in order to produce coppice. 

Wounds are produced on fruit-trees by removal of branches, by 
pruning and grafting, and again during the fruit-harvest. Hail 
and wind are frequent sources of wounding. Gnawing of the 
bark by animals, such as mice and other rodents, may also occur. 

lied deer, by peeling T)ff the bark, are a source of great 
damage in the forest. In this way spruce plantations may be 
so peeled, and in consequence so subject to red-rot that they 
have to be prematurely felled. The trees which suffer most 
are those like spruce, silver fir, Weymouth pine, and Douglas 
fir, whicli remain for a considerable time smooth-barked, whereas 
species with a rough bark are comparatively safe ; the latter 
can also cover up any wounded surface by means of an excretion 
of resin. Conifers suffer most from peeling, but the broad- 
leaved trees are not quite exempt. At certain seasons the deer 
rub the fur off the young antlers or knock off the old ; for 
this purpose they generally choose younger plants, which, in 
consequence of the injury, frequently dry up. Injury by deer 
is more serious in summer than in winter, because with the 
increased temperature and moisture the spores are able to 
convey infection quickly and easily. 

Injuries similar to peeling bv deer are produced in gathering 
resin, and in the process of “ testing ” the timber of conifers. 
Both practices are, however, prohibited in well-managed forestry, 
and occur only as misdemeanours. Resin-collecting of whatever 


PREVENTIVE AND COMBATIVE MEASURES. 


79 


kind, whether from spruce, larch, pine or the silver fir, necessi- 
tates removal of the bark, and probably cutting into the wood 
itself. The exuded resin and naked wood dry up in course of 
time and crack, thereby allowing the entrance of fungus-spores, 
which germinate in the fissures of the wood and lead to its 
destruction. 

The forests of spruce and fir in Bavaria furnish valuable 
wood suitable for the manufacture of violins and other musical 
instruments. Till recently the practice was first to split a test- 
piece from the standing tree to ascertain the cleavage of the 
stem. If the test did not split true, the tree was left standing 
and wounded ; such stems naturally were soon attacked by fungi 
(Polyporeae and Agaricini) and succumbed to some storm. 

The beech is frequently injured in a somewhat similar manner 
by the woodmen, who hew out large pieces of the stem to obtain 
material for wedges from the very tough occlusion-tissue which 
is afterwards formed. Stems so damaged soon fall a prey to 
Polyporus fomentarius. Wounds to the wood are also frequently 
produced during the felling of neighbouring trees, or as a result 
of storms, or by the action of woodpeckers, ants, and other 
enemies. In short, wounds are so common that the necessity 
of practical remedial measures for closing them as entrances 
for destructive parasites, must be at once evident. 

(2) Localities should be avoided which are known to pre- 
dispose certain plants to disease. Just as one avoids cultivating 
tender plants in cold situations, or planting our less hardy 
trees in places known to be liable to frost, so ought we to 
avoid the cultivation of plants in localities which will render 
them more than usually liable to infection by fungi. Thus the 
formation of spruce-nurseries at considerable elevations has had 
to be abandoned, because it was observed that they were there 
liable to complete destruction by Hcrpotrichia nigra. For 
similar reasons the hole-planting of spruce in elevated situations 
must be avoided. In moist localities nurseries of Douglas fir 
and other trees are in danger of attack from Botrytis ; while 
close glass-houses and hot-beds are breeding-places for many 
parasites which would at once die away with good ventilation. 

(3) The neighbourhood of plants which are supplemental 
hosts of the same heteroecious fungus should also be avoided. 
(See also p. 74.) 


80 


PREVENTIVE AND COMBATIVE MEASURES. 


(4) The massing of numbers of the same species of plant 
together is dangerous, because it presents a favourable oppor- 
tunity for the rapid spread of epidemic diseases. On this 
account the smaller fields of small holdings tend to prevent 
any epidemic from assuming serious proportions. Still better 
is a system where, as in Northern Italy, a few rows of vines 
alternate with narrow strips of Indian corn with gourds or 
melons on the ground below, and strips of grass or millet 
intervene here and there. 

Wherever similar plants must be cultivated in close neigh- 
bourhood over extensive areas, as in vine cultivation, any 
epidemic, which may obtain a hold, soon produces disastrous 
effects. Our cultivated forest plants, when occupying extensive 
areas, are particularly open to attacks of certain fungus-diseases. 
Thus Pines from Hysterium pinastri, Caeoma pinitorquum, and 
Peridermium pini ; pole-forests of pure spruce from Hysterium 
macrosporum, all plantations of conifers from Trametes radi- 
ciperda and Agaricus milieus, the latter especially if preceded 
by beech forest, the stools and dead roots of which offer the 
Agaricus an opportunity for easy and abundant development. 

The prevention of many epidemic diseases is one of the 
advantages claimed by Gayer 1 in favour of natural regeneration 
and mixed plantations. On exposed areas the prevailing strong 
winds facilitate distribution of many fungus-spores, while, at 
the same time, they introduce the supplemental hosts of 
of heteroecious fungi (e.g. aspen, ragwort, cowberry, etc.), which 
would be excluded from a closed permanent mixed forest natur- 
ally regenerated. Of course, we do not maintain that, under 
these conditions, diseases are entirely absent, because it is just 
on naturally-sown beech seedlings in closed forests that Phytojih- 
t.hora finds a habitat. Similarly Tricliosphacna on silver fir, 
and other parasites, are in closed forest provided with that 
degree of atmospheric moisture which favours them. In fact, 
several parasitic fungi exhibit adaptations to such conditions. 
Diseases, speaking broadly, are less dangerous in mixed forest; 
they never attain the same distribution, and they are more 
easily restricted where trees of different dispositions are grown 
together. Thus, the forests of Bavaria consist, in the lower 
elevations, of mixed beech, silver fir, ami spruce ; higher up 

'Gayer, Jhi- U'nldhau. 


PREVENTIVE AND COMBATIVE MEASURES. 


81 


the beech is omitted, and in the more elevated parts spruce 
alone is planted. The fir alone is attacked by Plioma abietina 
Aecidium elatinum, Lophodermmm nervisequium, Trichospliaeria 
parasitica ; the spruce, on the other hand, has to itself 
Lophodermium macrosporum, Chrysomyxa abietis, Herpotrichia 
nigra, while both are subject in youth to Pestalozzia Hartigii , 
and later to several wood-destroying fungi. 

The storing together of crops like apples, potatoes, onions, 
turnips, etc., should be carefully carried out. They should be 
handled as little as possible, and decaying individuals should be 
sought out, and destroyed when possible, to save the remainder. 


IV. Selection of hardy varieties. 

An important method for the protection of plants from disease, 
both from the preventive and remedial side, consists in the 
selection and cultivation of varieties and species of plants able 
to resist the attacks of parasitic fungi. 

It has already been mentioned that different varieties and 
species show different powers of resistance against enemies. As 
a further example, we have numerous American grape-vines 
which are not attacked by downy mildew ( Plasmopara viticola),. 
that dangerous enemy of the European vine of cultivation 
( Vitis vinifera). Some American vines (e.g. Vitis riparia ) 
are proof against the phylloxera, the root-louse which attacks 
the roots of European vines and devastates the vineyards of 
the wine-producing countries ; while, on the other hand, other 
American vines are no more resistant than the European. In 
fact, it was the importation of those vines into Europe for 
experimental cultivation which brought us both phylloxera and 
the downy mildew. The cultivation of such disease-proof 
species would ensure us immunity from the phylloxera, if it 
were not that the wine from these vines has neither the quality 
nor the flavour possessed by the European. On this account 
the grafting of European vines on American stocks has been 
introduced, whereby the roots remain unattacked by the 
phylloxera, and the grapes are of the approved standard. Very 
good results have also been obtained from experiments in 
hybridization of American and European vines with the object 
of obtaining roots from the American parent, and grapes from 

F 


82 


PREVENTIVE AND COMBATIVE MEASURES. 


the European. The long and patient experiments of Millardet 1 
are the most conspicuous amongst many which, by means of 
grafting and hybridization, have aimed at obtaining disease-proof 
vines. Millardet, out of numerous hybrids raised by him, has 
succeeded at last in obtaining vines with roots proof against 
phylloxera, leaves resistant to attacks of downy mildew, and 
grapes which impart the esteemed flavour to the various old 
and well-known European wines. From these many ruined 
vineyards of southern France have been already re-stocked, and 
promise well. 

The results obtained from Eriksson’s investigations on cereal- 
rusts are also worthy of notice . 2 This investigator, after carrying 
on cultivations for a number of years, has found that there are 
varieties of wheat able to resist the more frequent forms of 
rust, and in no way endangered by them. By a similar method 
of investigation, varieties suitable for cultivation in the rust- 
infested districts of Australia have also been obtained. 

1 Millardet, “ Notes sur les vignes americaines.” Ser. in. Mem de la sor. des 
■sciences de Bordeaux, 1891; Journ. d’cu/riculture pratique, 1892; Compt. rend., 
1894; Zeitsrhrift f. PJtanzenkrankheiten , 1894, p. 47, and 1895, p. 116. 

Esser, “ Die Bekampfung parasit. Pflanzenkrankheiten,” Samml. wisaensch. 
Vnrtrdqe ; by Virchow u. Wattenbach, 1892. With Bibliography. 

- Eriksson. Zeitsrhrift f. PJtanzenkrankheiten, 1895, p. 80. 


CHAPTER VII. 


ECONOMIC IMPORTANCE OF DISEASES OF PLANTS. 

§ 13. The economic importance of any plant-disease depends on 
its distribution, its intensity, and the value of the plants attacked. 
Of most consequence are those epidemic diseases of fungoid origin, 
which cause rapid deatli of their host, and spread with great 
rapidity over wide areas. Such, through repeated attacks, 
may render the cultivation of certain plants impossible 
in a locality. Almost equal damage may result from those 
parasites, which, although they do not kill their host, yet 
destroy or prevent the development of that part for which we 
grow the plant. Amongst these are species which inhabit 
flowers or fruits, the wood-destroying fungi of forest-trees, 
and forms inimical to the foliage, roots, or tubers of plants 
of economic value. 

As examples of parasitic fungi which bring about rapid death 
of their host, are the originators of many diseases of young 
plants. Phytophthora omnivora may during a few days of damp 
weather completely kill out not only healthy beds of seedling 
beech or conifers in the nursery, but even the young plants 
by which a forest is being naturally regenerated. Pestalozzia 
Eartigii, a few years ago in the beech-forests in some districts 
of Bavaria, exterminated three-fourths of the naturally-sown 
plants from one to four years old. Herpotrichia nigra is 
capable of completely destroying the young spruce plantations, 
so important for the afforestration of bare slopes in mountainous 
districts, and it may attack with such violence nurseries 
established at great cost and labour that they have to be 


84 


ECONOMIC IMPORTANCE OF DISEASES OF PLANTS. 


abandoned. "Whole gardens of roses have been devastated by 
Peronmjjora sparsa, and nurseries of conifers have been exter- 
minated by Hysterium pinastri, or Agaricus rn.dle.us. 

Amongst the fungi, which attack the organs of older plants 
and cause serious losses to cultivators, ctre the following : the 
well-known potato disease caused by Phytophthora infestans ; 
the vine diseases arising from Uncinvla spiralis, Plasmoparo 
viticoln, and Dematophora necatrix ; many diseases of conifers 
and other trees. As destroyers of the fruit alone may be 
mentioned the smut-fungi of the cereal crops. 

Other cases of injurious diseases, of more or less practical 
import, will be described in the special part of this book ; at 
present we shall only select a few estimates of the loss result- 
ing from them. 

In the forest of Bisclioffsreut in Bavaria — a magnificent one, 
containing spruce, fir, and beech — eighteen per cent, of the 
felled timber consisted of wood rendered useless by decay ; 
while fifty years ago the utilizing of the so-called fungus-sponges 
of Polyporus fomentarius in the same forest for manufacturing 
purposes and for tinder, was let for a small sum (see p. 74). 

Higher figures are, however, reached when we calculate the 
injuries on vines or cereal crops. Pierce, 1 in 1892, furnished 
estimates putting the loss resulting from the Anaheim vine- 
disease in California at ten millon dollars. The area of infected 
land was about 25,000 acres, in great part with an original 
value of 300 to 500 dollars per acre, but so depreciated in 
the course of five years that it became worth not more than 
75 to 200 dollars. 

In the Zntschrift fur Pfla nznikm nkhcitrn 1893, the inter- 
national phytopathological commission gave, from estimates 
mates furnished by the Prussian statistics-bureau, a review of 
the losses in Prussia from grain-rust. Amongst other esti- 
mates we find that in 1891 the wheat harvest of Prussia 
reached a total of 10,574,108 doppelcentner, 2 which at 22 
marks per d.c. = £1 1,459,090 sterling. Of this 3,310,059 d.e. or 
£3,593,758 was depreciated by rust. The rye harvest was 
30,505,008 d.c. at 22 marks, of which 8,208,913 d.c. 
or £8,890,304 was depreciated by rust. Oats reached 

1 The California Vine- Disease. U.S. Dept, of Ar/riculturr, Hull. 1892, |>. IS. 

- Doppelcentner = 100 kilogramme. 


ECONOMIC IMPORTANCE OF DISEASES OF PLANTS. 


85 


32 , 165,473 cl.e. at 16 marks, of which 10,325,124 d.c. 
•or £8,138,023 falls to be deducted on account of rust. 
Thus on the crops wheat, rye, and oats, the loss reached the 
sum of £20,628,147 sterling, or almost a third of the total 
value of the crops. The year 1891 was a very unfavourable 
one, but even taking the estimate at the half of the above 
sum we have a yearly loss by rust amounting to £10,000,000 
sterling. 

In Australia the loss in the wheat harvest of 1890-91, on 
account of rust, has been estimated at £2,500,000 sterling. 

Consideration of the loss of sums of money like these, which 
might be considerably reduced if energetic and universal measures 
were employed against fungoid plant-diseases, will serve to em- 
phasize the importance of remedial measures. It must also he 
borne in mind that the use of diseased fodder, 1 especially hay, 
grass or grain, infested by rust or smut-fungi, is productive of 
serious results to the various animals of the farm ; while the 
use of meal or flour contaminated with smuts, stinking- smuts, or 
•ergot is dangerous for mankind. 


1 Frohner, Lehr buck d. ToxiJcologie f. Thierdrzte, 1890. 


CHAPTER VIII. 

SYMBIOSIS. 

§ 14. MUTUALISM. 

Mutualism, or Symbiosis in the stricter sense , 1 lias been 
distinguished as a special case of parasitism. This condition 
occurs when a parasite and its host mutually work for 
the benefit of one another, each contributing to the other’s 
nourishment. The lichens furnish the most conspicuous example. 
Here fungus-hyphae unite with algal cells, the algae furnishing 
the fungi with assimilated organic nutriment, the fungi pro- 
viding water and dissolved salts for the algae. 

While it is by no means uncommon to find two organisms 
taking a mutual advantage of each other, yet mutualism in its 
strictest sense is a rare phenomenon. For it generally happens, 
and is indeed to be expected, that one or both symbiotic 

organisms modify in some degree their mode of life to suit the 

altered conditions necessary for their mutual support. Thus 

amongst the lichens, as a result of the union of fungus and 
alga, a living organism originates, which in form, necessities, 
and mode of life is quite new , and differs completely from 
either of its components. In the lichen-community, the fungus 
alone reproduces itself ; yet the alga occurs as a free organism 
in nature, while the fungus can only be reared in artificial 
culture. This combination might perhaps be compared with 

that of oxygen and hydrogen to form water, also to a certain 
extent with the union of the sexual cells to produce a new 

1 The term Symbiosis was applied by De Bury, (who introduced it), by Frank 
and others, to denote those cases where a cohabitation or partnership was. 
observed to take place between two different organisms. (Frank, l.thrbuch <1. 
Botanik, 1892). “ Mutualism” was first used by Van Beneden. 


MUTUALISM. 


87 


individual. These, and other examples, will serve to illustrate 
how we have in the lichen an organism with peculiarities of 
structure and of life, widely differing from those of either an 
alga or a fungus. This unification of two living beings into an 
individual whole, I have designated “ Individuation .” 1 

In the case of the lichen-symbiosis, the chlorophyllous part 
consists of minute dlgal cells, completely enclosed in a tissue 
of fungus-hyphae, and the lichen lives as a perfectly isolated 
and independent plant. The case is, however, different where 
the fungus enters into parasitic relationship with the green 
cells of a large plant. Union may then take place, so that the 
fungus lives on, or inside its host, and removed from contact with 
any other substratum. The fungus is, however, not in a position 
to convey any nourishment to its host, and in fact is absolutely 
dependent on it for the organic substance and water necessary 
for growth. Where, however, the relationship is such that the 
parasitic fungus is still in contact with some other substratum, 
then it may be assumed that, in spite of its parasitism, it 
takes up nutriment from this source, and shares it with its 
host. This, as has already been pointed out, is the state of 
things in the lichens, where the fungus completely envelopes 
the small isolated algae, and must, as a condition of the growth 
of the lichen, remain in direct contact with the substratum ; 
the fungus is believed to take from the substratum water and 
inorganic food-material with which it supplies the algae, while 
it receives in return plastic organic substance to be used in 
its own growth. Of course cases do occur amongst the lichens, 
where, in moist places, the alga is not dependent on the fungus, 
or, on the other hand, where the fungus can itself take up 
organic substance from its substratum. 

Another example of the case is the union of fungi with 
non-chlorophyllous plants which inhabit humus (e.g. Mnnotropa). 
Here the fungus takes up organic nourishment from the 
substratum and supplies it to the higher plant, which, in 
consequence of its lack of chlorophyll, is directly dependent on 
the plastic organized substance from the soil, supplied through 
the agency of the fungus. The latter, however, receives nothing 
in return ; it requires nothing, since its substratum offers it 
the most favourable conditions for nutrition. This form of 


1 Individualismus. 


88 


SYMBIOSIS. 


symbiosis, in which the fungus becomes the nurse or feeder, I 
distinguish as Nutricism. Between the case just cited and 
that in which the fungus is a pronounced root-parasite on 
green plants, there exists every possible intermediate stage. 

Before nutricism is considered in detail it would be well to 
exemplify briefly from the ranks of plant-parasites, that pheno- 
menon of individuation so sharply defined in the lichens. 
A large number of p>arasitic fungi cause local cell-enlargement and 
cell-increase, with the frequent result that an attacked plant- 
organ becomes very much enlarged and its form much changed. 
One speaks in such cases of hypertrophy and hypertrophied 
organs. It is quite evident that in cases of hypertrophy the 
attacked part must be better nourished, otherwise it could never 
sustain the great increase in number and size of its cells. The 
hypertrophied organ is, in fact, indebted to the surrounding 
healthy parts for its additional nourishment ; in other words, 
the place of demand draws to itself the materials it requires. 
This is all the more necessary when the region of increased 
growth is deficient in, or altogether devoid of, chlorophyll, and 
thus quite dependent on the assimilating green parts. This 
is frequently the case, as in the scales of alder catkins attacked 
by Emascw alni incanae, in the needles of silver fir deformed 
by Arculinm elatinum, or in the yellow needles on spruce 
resulting from AaAdium cormcans. So also must the woody 
swellings of branches attacked by Accidium rlatinum, Gf/mno- 
xpuranyium sabinar, and other fungi, be produced at the cost of 
neighbouring parts of the host. The hypertrophied organs be- 
have, in fact, like these plant-organs — flowers, roots, etc. — 
which are normally deficient in chlorophyll, and to which 
plastic material must be supplied. 

In other cases the part of a plant attacked by fungi behaves 
like a specialized organ, and, in combination with the fungus, 
attains to a certain degree of independence. The so-called 
'‘witches’ brooms” furnish an interesting example. It is a well- 
known fact that the direction of growth of the main axis of 
plants is negatively geotropic, whereas that of the lateral branches 
is only a modified form of this condition. If the terminal bud 
of a tree (c.g. a spruce or fir) be removed, then one or more 
lateral branches, or even buds of those branches, will exhibit 
an increased negative geotropism. This is very marked in 


MUTUALISM. 


89 


the case of the so-called “ storm-firs ” of the mountains, on 
which are developed not a single apex, as in the normal fir, 
but many, each of which grows up like a little independent 
tree on the branches of the old stem. A similar result follows 
where a portion of a lateral branch is planted as a “ cutting,” 
one bud grows directly upwards, the others form lateral branches. 
The stimulating effect which the removal of the terminal shoot 
produces on lateral branches is thus one which extends to a 
considerable distance. A stimulus of a somewhat similar nature 
appears to be exerted on buds attacked by certain fungi, so 



Fig. 16. — Witches’ broom of Silver Fir, caused by Aecidium, elatinum. 
(v. Tubeuf phot.) 


that the shoot produced from such a bud no longer retains its 
normal direction of growth, but becomes negatively geotropic 
like an independent plant. This marked negative geotropism 
is characteristic of all witches’ brooms (Fig. 16), and shows 
clearly that they are no longer controlled by the same laws of 
growth as the normal lateral branches. They have in addition 
other peculiarities not exhibited by normal plants. Thus the 
wdtches’ broom of the silver fir caused by mycelium of 
Aecidium elatinum is not evergreen, . but bears needles which 
fall each autumn. Moreover, no witches’ broom bears flowers 
or fruit ; for example, that on the cherry (Fig. 5) produces 
exclusively leaf-buds which unfold simultaneously with the 



90 


SYMBIOSIS. 


opening of the flower-buds of unattached twigs, the normal 
foliage coming later. 

We have here an expression of the existence of a closer 
symbiotic relationship between the fungus and its host- branch, 
than between that host-branch and its main branch. It also 
shows that the host-branch is completely at the service of the 
fungus, although the latter is dependent on the former for its 
support. The host-branch is, at the same time, under the 
necessity of conducting itself in the partnership in the way most 
suitable to the development of the fungus. 1 Thus the asci of 
the Exoasceae are produced on the leaves of the witches’ broom, 
and ripen as the normal leaves unfold, so that the spores 
are in a position suitable for successful infection of the young 
normal leaves. 

From these facts it can be deduced, that parts of plants 
attacked by fungi exhibit that kind <>f symbiosis with the fungus 
which we call individuation, the joint community behaving 
more or less as a parasite on the stem or 1 (ranches of the host- 
plant. This is clearly the case where the attacked parts exhibit 
increased growth, and at the same time a diminished production 
of chlorophyll resulting from degeneration of chloroplasts. Such 
parts of plants are quite as individualized as the lichens, with the 
single distinction that they remain in communication with the 
parent plant and draw nourishment from it. 

There are, however, other cases where the chloroplasts are 
apparently increased, where at least they attain a lengthened 
duration of life. This is evident in certain instances first 
pointed out by Cornu, mentioned by De Bury, and on 
which I have made extended observations. Maples may 
lie found in autumn on whose discoloured, withered leaves 
large green spots are still present. On Norway maple I have 
observed these spots, very conspicuous on almost every leaf, 
and especially on those of the lower crown. The green parts 
were beset with the white epiphytic mycelium and perithecia 
of Uncintda aceris. Cornu describes similar appearances accom- 
panying another Erysiphc, certain I redineae, and Oladosponuui 
dendriticum. 1 have seen the same phenomenon regularly on 
the mountain maple on leaves carrying black spots of Ehj/tisma 

1 Plant-galls caused by animals also exhibit adaptations serviceable only for 
the gall-occupant. 


MUTUALISM. 


91 


pvnctatum (Fig. 129). As other examples may be mentioned 
quince leaves, which I infected with Gymvosporangium clavariae- 
forme, and leaves of Cynanchum Vincetoximm infested with 
Cronartium asdepiadeum. In all these cases, nutritive sub- 
stances seem to be still transmitted to attacked parts after 
death of the rest of the leaf. The attacked spots show also 
an independent behaviour in that they do not turn yellow 
before the fall of the leaf, but continue to work at the 
service of the parasite. One can even believe that these green 
islands, so long as inorganic substance and water are supplied 
to them, live with the fungus like lichens, especially those 
lichens whose algae obtain water and inorganic material direct, 
not through the fungal-hyphae. 


CHAPTER IX. 

SYMBIOSIS. 

3 15. NUTRIC'ISM. 

For the greater number of the facts used in our discussion 
of this peculiar phenomenon, we are indebted to Frank, who 
laid the basis of our knowledge in regard to it. We have 
chosen the expression Xutricism for reasons already stated 
(§ 14), and would only add that its scope is variable in different 
cases, and reaches its most comprehensive application in connec- 
tion with Frank’s views on the so-called inycorhiza. We shall 
best explain the phenomenon by describing individual examples. 

In a number of cases the symbiosis between fungi and higher 
plants does not result in the fungus being supplied with organic 
nutriment by its host, but rather that the fungus is in no way 
indebted to the host-plant for nutriment, and may even, as in the 
lichens, convey solutions of inorganic materials to it, thus assist- 
ing in its nutrition. There are two cases distinguishable in this 
connection. In the first, the fungus lives in humus and in 
close external oontact with the roots of its host, obtaining 
food for itself, and at the same time supplying its host 
with organic nutriment. In the other case, the fungus develops 
inside the root-cells of its host, and is probably nourished from 
that source, till on dying it gives up certain albuminoid sub- 
stances, which are absorbed and utilized by the host-plant. The 
parts of the roots which shelter the fungi, Frank has named 
“ fungus-traps,” the plants themselves being “ fungus-digesting 
plants.” 

The organs resulting from the symbiosis of root and fungus 


NUTRICISM. 


93 


have been named mycorhiza 1 or fungus-roots. Where, however, 
new structures (swellings, etc.) are produced on the roots, as a 
result of symbiosis with fungi or bacteria, the name mycodomatia 
or fungus-chambers has been applied. 

One division of mycorhiza consists of those which live in 
humus, and act as intermediaries in supplying their hosts with 
nutritive material. In this case the fungus covers the host- 
root like an outer covering, forces itself between the cells of 
the outer layers, and produces haustorial branches in the interior 
of the host-cells. These Frank designates as ectotrophic 
mycorhiza. The remaining mycorhiza do not form such an 
external sheath, but live inside the fungus-traps, and produce 
tangled coils of hyphae in the root-cells of the host. These 
Frank distinguishes as endotrophic mycorhiza. 


Ectotrophic Mycorhiza. 

(1) On non-chlorophyllous plants living on humus. 

Kaminski 2 was the first to observe that Monotropa hypopitys, a 
non-chlorophyllous plant living rooted in forest-mould, possessed a 
compact root system devoid of root-hairs, but covered with the 
hyphae of a fungus. At the same time, he expressed the belief 
that a symbiotic relationship existed between the fungus and 
the roots of Monotropa, whereby the former supplied nutriment to 
the latter. The fungus clothes the growing point, and extends 
backwards to that part of the root which has ceased to elongate; 
there the mycelium penetrates 3 inwards between the root-cells, 
and remains intercellular. The mycorhiza of Monotropa thus 
showed complete agreement with those known earlier on the 
roots of Cupuliferae , 4 and since proved by Frank to have a very 
general distribution. Johow 5 has pointed out that an external 
mantle of fungi also exists round the root-apices of Hypopitys 
hypophaegea, a holosaprophytic plant devoid of chlorophyll. 

1 Sarauw, Rodsymhiose og Mycorrhizer saerlig hos Skovtraerne, 1893. With 
Bibliography. 

2 Kaminski, Mini, de la soc. des sciences natur. de Cherbourg , T. 24, 1882. 

3 Frank, Berichte d. dewtsch botan. Ges., 1885. 

4 Muller, Sludier over Skovjord som Bidrag til Skovdrykningens Theori, 1878. 

5 Johow, “ Die chlorophyllfreien Humuspflanzen,” Pringsheim’s Jalirbuch, 1S89. 


94 


SYMBIOSIS. 


(2) On chlorophyllous plants. 

Frank has extended Kaminski’s theory to include the 
inycorhiza of trees and other green plants. This assumption 
is founded on his observations of the common occurrence of 
inycorhiza on the Cupuliferae, and many other plants. He says 
that all trees are probably capable, under certain conditions, 
of entering into symbiosis with mycorhiza-fungi, and that in 
this way the tree is supplied not only with the necessary water 
and mineral food-constituents from the soil, but also with organic 
material derived directly from humus and decaying plant-remains. 
The tree is thus enabled, through the inycorhiza, to directly utilize 
organic vegetable remains. Frank supported this theory by 
anatomical investigation of the inycorhiza of numerous plants 
and later by physiological experiments. The latter consist in the 
comparative cultivation of seedling forest-trees in a sterilized 
humus-soil, and also in a non-sterilized soil containing the 
mycorhiza-fungi. These experiments showed, in the case of 
beech, that those trees in sterilized soil with normal roots and 
root-hairs without inycorhiza, were poorly developed, and died 
after several years, while the others with inycorhiza grew 
vigorously. 

Frank also pointed out that inycorhiza are developed only 
in soils containing humus, and in the lnimus layer. He 

assumes that the fungus conveys to the tree-roots not only 

carbon compounds, but also, since the mycorhiza-cells contain 
no nitric acid, nitrogen in organic compounds. 

The mycorhiza-caps suppress the formation of root-hairs, but 
I have frequently seen hairs on neighbouring roots or on parts 

of the same root behind the fungus-cap (Figs. 17 and IS). In 

soil free from humus, root-hairs are always present and carry 
on their work normally. Schlicht 1 found that pines growing 

in poor sandy soil without lnimus had no inycorhiza, but only 

normal root-hairs, lieess found that pines near Erlangen had 
quite as many rootlets without inycorhiza as with. It would 
thus appear that while every tree possesses a number of roots 
with fungus on them, yet the complete transformation of the 
whole root-system to inycorhiza is by no means so general as 

'Schlicht, lining. Dissertation, Berlin, lSSi). p. *). 

Frank, It' r. <1. deutuch. botan. Qts,, 1 892, p. 683. 

Keess, lUr. <1. daU*rh. l>otan. (re*., 1SS5, p. ‘296. 


ECTOTROPHIC MYCORHIZA. 


95 



Fig. 17. — Spruce seedling in third year, grown in clay-loam. Typical coral-like 
mycorhiza are absent. The strong root to the right shows, on its newer parts 
and on all lateral roots, only root-hairs and no fungus. The remaining roots are 
not modified in any way — some are covered with loose fungal caps, others 
have both fungal caps and root-hairs, while others are quite free from fungi. 
<v. Tubeuf phot.) 



% 


SYMBIOSIS. 


in Monotropa. The root-system of a tree has not only to secure 
nourishment, hut also the rigidity and stability of the tree . 1 
This latter can only be attained by a wide distribution of roots 
in the firm subsoil free from humus, where normal roots with 
root-hairs will be formed. The nursing function of the mycorhiza 
seems thus to be less important than in the case of Monotropa. 




Fio. 18 . — Mycorhiza of Finns Cembra. A , Typical mycorhiza. Ii, Hoot showing 
clusters of mycorhiza as well as portions clad with fine root-hairs. C, Rootlet 
exhibiting button-like thickenings externally devoid of a fungoid mantle, but 
internally completely destroyed by mycelium. D, Section through a thickened 
branch of a mycorhiza -cluster : a, fungoid mantle ; />, fungoid tissue between 
the cells of the root, rendering them unrecognizable except by their large nuclei ; 
the inner parts contain no fungi, (v. Tubeuf del.) 


My newest investigations on this subject 2 show that , amongst 
the gymnospermous forest-trees, the Abietineae alone have roots 
externally clothed with a fungus ; the remaining groups have 
all endophytic mycorhiza. The Abietineae have frequently only 
a fine mantle of fungus on their rootlets, and do not produce the 
tufts of short, branched roots so characteristic of mycorhiza in 
general. Frank does not seem to lie altogether correct in his 
view that the Abietineae are almost or quite incapable of multi- 
plication by slips, because they would then require to exist for a 
time without mycorhiza. Probably there is some other reason 
for this, because the Salicaceae (>.</. Poplars), which have typical 
coral- branched mycorhiza, are almost exclusively multiplied by 
slips. 

1 Huveler, (“ttb. die Verwerthnng d. Humus bei d. Emnhrung d. chlorophyll 
fuhrenden Pflanzen.” Inaug. Piss., Berlin, 1892}, states that roots are able to 
utilize the soil-constituents without aid of fungi. 

-Tubeuf, Forul.-nalurwixu. Zritxchrip , 1896. 


ECTOTROPHIC MYCORHIZA. 


97 


After the mycorhiza have functioned as such for some time, 
the fungoid sheath, as well as the hyphae contained in the 
cortex of the root outside the endodermis, are thrown off by 
internal cork-formation. This is, however, not always the case, 
for the fungus may penetrate further and develop injurious para- 
sitic characteristics; this is so with Polysaccurn 1 and Elaphomyces . 2 

Endotrophic Mycorhiza. 

(1) On non-chlorophyllous plants living in humus. 

Certain Orchideae — Neottia Nidus avis, Epipogon Gmelini, 
Gooclyera repens, etc., as well as some Gentianeae , 3 possess 
roots developed as endotrophic mycorhiza. In Coralliorhiza the 
fungus frequents the short coral-like rhizomes. The fungus in 
these cases penetrates into the cells of the root-cortex, and 
there forms a ball or coil of hyphae ; it neither covers the 
roots externally nor inhabits the epidermal cells, so that the 
production of root-hairs goes on quite normally. From the 
circumstance that the hyphal coils become emptied and only 
the remains of walls are left in the still living root-cells, Frank 
concludes that the fungus after being nourished for a time by 
the root-cells is ultimately deprived of its contents by them. 
On this account he calls these roots “ fungus-traps,” and the 
plants possessing them “ fungus-digesting plants.” It must be 
remarked, however, that the fungus grows onwards from older 
parts of the roots to younger, so that here, as in many other 
cases, the contents of the hyphae may pass from the older into 
the younger hyphae. Frank himself suggests 4 the possibility 
that the roots take up nutriment without aid from the enclosed 
fungus, and also that the latter receives its food parasitically 
from the former. What advantage the roots may receive from 
reabsorption of food, which they have previously supplied to the 
fungus, has not been closely investigated, nor has the question 
whether the roots are in a position to nourish the plants equally 
well without fungi. 

The root-fungi of Orchideae have long been known, and Pfeffer 5 

'Bruns, “ Beitrag z. Kenntniss cl. Gattung Polysaccurn,” Flora, 1S94. 

2 Reess, “ Untersuch. liber d. Hirsclitriifl'el,” Bibliog. Botan. 1887. 

:i Pringsheim’s Jahrbuch, xvi. and xx. 

4 Frank, Lthrbuch <1. Bolanik p. 267. 

G 


5 Landwirth. Jalirbuch, 1877. 


98 


.SYMBIOSIS. 


suggested that the reduced formation of hairs on their roots was 
due to the fungus-hyphae behaving physiologically as root-hairs. 

Johow, in opposition to Frank, states that the non-chloro- 
phyllous Wullschlaegelia, a relative of Neottia, shows no trace of 



Fin. 19 . — Coralliorhizo inno.ta Br. 
(v. Tubeuf phot.) 


Fin. 20. — Neottia Ni<ius avis Rich. 

(v. Tubeuf phot.) 

fungal hyphae about its roots, and yet derives nourishment direct 
from humus. The same author found among roots of the Bur- 
manniacme, some free from fungi, and some with the rind, and 
even the epidermis full of mycelium. 

(2) On chlorophyllous plants living amongst humus 

According to the investigations of Frank, all our Ericaceae, 
Epacrideae, and Fmpetraceae, living in the humus of moor, heath, 




ENDOTROPHIC MYCORHIZA. 


99 


or wood, possess endotrophic mycorhiza. These appear as fine, 
elongated rootlets whose epidermal cells never develop as root- 
hairs, but become filled with coils of fungoid hyphae. 

Schlicht mentions a large number of herbaceous plants out of 
the most widely separated genera of Angiosperms, the finer roots 
of which he found regularly developed as mycorhiza. These, how- 
ever, possess in addition normal root-hairs, which without doubt 
function as such. The endotrophic coils of fungi are situated in 
the inner cells of the cortex surrounding the conductive tissues, 
and Schlicht regards them as important in transmitting to the 
conducting tissues substances taken up by the root-hairs. Since, 
however, the fungus inhabits living cortical cells, it is quite 
possible that these transmit the food-materials direct without 
the aid of the fungus. 

Schlicht found endotrophic mycorhiza on Leguminosae, while 
Frank found them on the alder, both being distinct from the 
well-known tubercles of these plants. 

Kuhn 1 and Goebel 2 found endophytic root-fungi on Marat- 
tiaceae, Ophioglosseae, and lycopodium ; Kuhn also found spores 
which resembled those of Schinzia. 

Endotrophic mycorhiza are also present in saprophytic green 
orchids, as well as in hemi-saprophytic orchids without green 
colour; and Meineke 3 found hyphae passing through the little 
cells of the endodermis of the aerial roots of orchids into the 
mucilage-masses of the rind-parenchyma. Schimper found fungi 
present on the adherent side of the roots of epiphytic orchids. 


Mycodomatia of Myricaceae, Elaeagnaceae, and the 

Alder . 4 

The above-mentioned plants possess a well-developed and 
normal root-system, and also characteristic lateral outgrowths, 

1 Kiihii, “ Untersuchungen iib. d. Anat. d. Marattiaceen,” Flora, 1889. 

2 Goebel, Botau. Zeitung, 1887. 

3 Meineke, “ Beitr. z. Anat. d. Luftwurzeln d. Orchideen,” Flora , 1894. 

4 Bibliography — Woronin, Mim. de Vacad. des sci. de St. Petersburg, 1866. 

Brunchorst, Ber. d. deutsch. botan. Ges., 1885. 

Brunchorst, U liters . aus d. botau. Inst. Tubingen, 1886. 
Moller, Ber. d. deutsch. botan. Ges., 1885 and 1S90. 

Frank, Ber. d. deutsch. botan. Ges., 1887 and 1S89. 
Atkinson, “ The genus Frankia in U.S. America,” Torrey 
Club Bulletin, 1892, p. 171, with plate. 


100 


SYMBIOSIS. 


which may increase to very large tubers, with surfaces resemb- 
ling a bunch of grapes (Fig. 21). In the large cells of the 
middle layers of the primary root-cortex of these growths, 
coils of very tine fungus-threads are sheltered ; these extend 
year after year into the younger parts of the enlarging tuber- 
cles, and gradually disappear in the older parts. What may 
be the significance of these structures for plants possessing 



Fio. 21 . — Frankia alni. Root- tubercles on the Alder, (v. Tubetif idiot.) 


chlorophyll and furnished with normal roots is as yet unknown. 
Plants which have grown well for years in water-cultures do not 
show them. On account of the cork-covering with which these 
tubercles are furnished, it would seem that they are not adapted 
for taking nourishment out of the soil. 

Woronin described them first on the alder, Warming on 
Klaeagnaceae, while Midler proved their fungal origin. 

The species of fungi which produce these tubercles have been 


MYCODOMATIA OF THE ALDER, ETC. 


101 


provisionally distinguished as Frankia alni (Wor.) on alder, and 
Frankia Brunchorstii (Moll.) on Myrica Gale. 

Hiltner , 1 after a series of experiments, states that first-year 
alders without tubercles do not thrive in soil free from nitrogen, 
nor do they take up nitrogen from the atmosphere ; when, 
however, provided with root-tubercles they assimilate nitrogen. 
The tubercles also functionate in water, and soil rich in nitrogen 
has the affect of slightly increasing the assimilation of that 
element. The tubercle-fungus is at first parasitic on the alder, 
and is only of use to the plant after the tubercles have fully 
developed. 


Mycodomatia of the Leguminosae. 


All Leguminosae growing in their native soils exhibit the 
so-called tubercles. These are accessory formations of the 
primary root-rind and are furnished with 
vascular bundles connected with the root- 
bundles ; they consist of a cortex of normal 
cells surrounding an inner large-celled 
parenchyma with turbid cell-contents con- 
sisting of numbers of bacteria, ( Bacterium 
radicola, Beyerink, or Rhizobium leguminos- 
arum, Frank.) 2 

Frank describes minutely the formation 
of these tubercles . 3 The short rod-shaped 
microbe forces its way into a root-hair 
or epidermal cell, multiplies there, and is 
conducted to the inner cortical cells by 
plasma-threads continuous through the 
cell-walls. A rapid division of the inner 
cortical cells is set up, till a tubercle is 
formed, which may still further increase 
by continued cell-division from a meristem 
at its apex. The bacteria multiply simul- 
taneously, and are transferred into the new cells where a 
great change comes over most of them ; they enlarge very 



Fig. 22. — Rhizobium legum- 
inosarum. Root-tubercles on 
Genista linctoria. (v. Tubeuf 
phot.) 


1 Hiltner, “ Ueber d. Bedeutung d. Wurzelknollchen v. Alnus glutinosa,” 
Xobbe’s Landwirtschaft. Versuchs-stationen, 1895. 

2 Woronin, Mem. de I’acad. des sci. de St. Petersburg, 1886. 

3 Lehrbuch d. Botcinik, p. 271. 



102 


SYMBIOSIS. 


much and become club-shaped or dichotomously branched 
bodies without power of division, which may be designated 
“ bacteroids .” 1 Brunchorst found the contents of the bacteroids 


Fio. 23 .— RhUobium IfguminoMirum. Hoot-tubercles on Robinia Pittulacacia 
(v. Tubeul phot.) 



to disappear at the time of the fruit-formation of the host- 
plant. A small number of microbe-bodies still remain, according 
to Frank’s observations, capable of division, and these, after 


According to Muller, they undergo fatty degeneration. 


MYCODOMATIA OF THE LEGUMIN OSAE. 


103 


decay and break-up of the tubercles, reach the soil ready to 
bring about new infections. 

The great importance of the tubercles of Leguminosae is 
that the plants bearing them are capable of taking up free 
nitrogen from the atmosphere and utilizing it, while without 
the tubercles they could not do so . 1 If Leguminosae be grown 
in soil rich in nitrogenous food-substances, the tubercles are 
not so well developed. 

According to Schneider , 2 the host-plant under the influence 
of the Rhizobium produces cellulose tubes, which become filled 
with the fungus. According to Beyerink , 3 these tubes consist 
of bacterial slime secreted by the Rhizobium. The epidermal 
tissue of the tubercles consists of a loose layer of cork with 
many intercellular spaces; this arrangement is stated by Frank 4 
to facilitate the usual transpiration . 5 

1 Hellriegel u. Wilfarth, Berichte d. deulsch. bo/an. Ges., 18S9; also Zeitschrft 
f. d. Ritbenzucker- Industrie, 1888. 

2 Ber. d. deutsch. botan. Ges., 1894, p. 11. 

3 Oentralbl. f. Bacterologie u. Parasitenkunde, 1894. 

* Ber. d. deutsch. botan. Ges., 1892. 

’Schneider (Bulletin of the Torrey Club, 1892), gives a short account of 
American Rhizobia, and refers to the chief works on this subject. (Edit.) 


PART SECOND. 

SYSTEMATIC ARRANGEMENT OF THE CRYPTOGAMIC 

PARASITES. 

r. THE PATHOGENIC FUNGI Oh' PLANTS. 

The vegetative body of the Fungi is a thalloid structure 
known as a mycelium, and composed of one or more hyphae. 
The hyphae are cells included in a firm wall of fungus-cellulose 
of varying composition ; they grow apically, and hence are 
always filamentous in shape. In the simpler cases, the mycelium 
is a non-septate tube unbranched or branched ; in the more 
complex forms, it consists of a system of hyphae divided into 
cells by cross-septa. By the union and anastomosing of numerous 
hyphae, a tissue may be formed not unlike the parenchyma of 
higher plants, hence receiving the name pseudo-parenchyma. 
From this tissue may arise distinct structures of many kinds, 
such as the sporophores of the Polyporeae, or strands of 
tissue like the well-known rhizomorphs of Agaricus mcUeva, 
or masses of resting-mycelium like the sclerotia of Clariceps. 
It is also not uncommon to find a differentiation in the structure 
of the vegetative mycelium in the form of lateral outgrowths 
of the hyphae, developed as organs for the collection of nutri- 
ment — the haustoria, — or as organs of attachment — appressoria. 

Reproduction may take place sexually by the union of two 
cells or nuclei, the product of which is a spore or zygote capable 
of germination ; or asexually by means of endogenous spores 
or swarm-spores, or by the abjunction of conidia of different 
kinds. Sexual reproduction is common amongst the lower 
fungi, but in the higher forms, if existent at all, it is very 


THE PATHOGENIC FUNGI OF PLANTS. 


105 


obscure and is replaced by numerous and complex modes of 
asexual multiplication. 

The lower forms of fungi, in the structure of the thallus, mode 
of reproduction, and adaptation to an aquatic life, exhibit distinct 
relationship with the Algae, particularly with the Sijrfioneac. 

Since the fungi do not possess chlorophyll, their nutrition 
is carried out by the absorption of organized material in a 
saprophytic or parasitic manner. Parasitic fungi are the cause 
of numerous and dangerous diseases of plants, whereas they 
only rarely bring about a diseased condition of the animal body. 
Bacteria on the other hand, which cause so many animal diseases, 
seldom affect plants injuriously. While many parasites are 
strictly limited to a parasitic mode of life, a large number 
naturally spend a part of their lives as saprophytes, and others 
may be made to do so artificially on nutritive substrata 
under suitable conditions. The latter method forms in fact a 
valuable aid for completing our imperfect knowledge of the 
life-histories of parasitic forms. In addition to the well-marked 
parasitic fungi, there are many saprophytic forms which become 
parasitic for a relatively short time or under special conditions 
of environment. 

The Fungi are divisible into two large groups, the lower 
fungi (Phycomycetes) and higher fungi (Mycomycetes). 

The systems instituted by various investigators differ not 
a little from each other. Three of the principal are : 


De Bart. 

(1) Phycomycetes 

(2) Ustilagineae 

(3) Ascomycetes 

(4) Uredineae 

(5) Basidiomycetes 


Zopf. 

(1) Phycomycetes 

(2) Mycomycetes 

(a) Basidiomycetes 

( b ) Uredineae 

(c) Ustilagineae 
(cl) Ascomycetes 


Brefeld. 

(1) Phycomycetes 

(2) Higher Fungi 

(a) Mesomycetes 
Hemiasci — Hemibasidii 

(b) Mycomycetes 
Ascomycetes — Basid io - 

mycetes 


We shall in the present work consider the Fungi in the 
following order : 

Lower Fungi or Phycomycetes : 

Chytridiaceae, Zygomycetes, Oomycetes. 

Higher Fungi or Mycomycetes : 

Ascomycetes. 

Ustilagineae, Uredineae, Basidiomycetes. 


106 


PHYCOMY CETES. 


A. Lower Fungi (Phycomycetes ). 1 

The lower fungi possess, at least in their earlier stages, 
single-celled mycelia, which may in the higher families become 
branched. They reproduce sexually by oospores or zygospores, 
asexually by conidia. The Phycomycetes are divided into : 
Chy tridiacme, Zyyomycetes, and Oomycetes. 

(1) CHYTRI DIACE AE. 

The fungi of this family are chiefly parasites on aquatic 
plants, or on land-plants inhabiting moist places. The my- 
celium is one-celled, very rudimentary, or altogether absent. 
Asexual reproduction takes place by the formation of zoo- 
sporangia which usually produce uniciliate swarm-spores. Sexual 
reproduction is rare, and is effected by fructification of one 
cell by a fertilization-tube from another ; the resulting bodies 
are zoosporangia which on germination set free swarm-spores. 
Hibernation is effected by resting-spores produced from sporangia 
in which the formation of swarm-spores is suppressed, and 
which become clothed in a thick membrane. Some of the 
species cause interesting deformations on the organs of plants. 

The Chytridiaceae include the families of Otpidiaccac, Synchy- 
triacmc, Cladochyf riaceae, Rhizuliaccac , Hypochytriaccar, and Oochy- 
triaceae. Of these, only the first three contain species parasitic 
on higher plants. They occur epidemic only in moist situations, 
and rarely cause great damage to cultivated plants. 

OLPIDIACEAE. 

The whole vegetative body becomes a single zoosporangium 
or a resting-spore. Sexual reproduction is very rare. 

Olpidium. 

The vegetative body consists of a naked mass of protoplasm, 
the product of a single spore. This becomes later enveloped 
in a thin wall of cellulose, and forms a zoosporangium with a 
long neck through which the cell-contents are ejected as 
uniciliate swarm-spores. The cellulose membrane may become 
thicker and a resting-spore (sporangium) result, which in course 
of time germinates and gives off swarm-spores. 

1 Bibliography A. Fischer in Rabenhorst's Kryptogamen Flora, 1 sag 
Sehroeter in Engltr- Prantl Pjlamenfamilim, 1 S0‘J. 


OLPIDIUM. 


107 


Olpidium brassicae, (Wor .) 1 ( = Chytridium brassicae, Wor.) 
Cabbage-seedlings die if this fungus finds its way into the tissue 
at the neck of the root. The spherical sporangia are formed at 
this place, and their long necks project out of the cells enabling 
the uniciliate swarm-spores to escape. liesting-spores with a 
warty thickened membrane occur in the cells of the epidermis. 



Fig. *24. — Chytridium brassicae , Wor. Cell containing three sporangia, two of 
which are discharging zoospores ; one sporangium is already empty. Resting* 
spores inside the cells of a cabbage-plant. (After Woronin.) 


The disease is favoured by moisture, and restricted by dry 
surroundings. Ground subject to attack should be planted 
with crops other than cabbage. 

Olpidium trifolii, Schroet. ( = Synchytrium trifolii, Pass.) 
Produces deformation of the leaves and petioles of Trifolium 
repens. The fungus lives in the epidermal cells. 

Olpidium lemnae, Fisch., in epidermal cells of Lemna. 

Olpidium simulans, De Bary and Wor., in Taraxacum 
officinale. 

A number of other species inhabit algae, spores, fungus- 
mycelium, pollen -grains, and eggs of Rotatoria. 

The genera Reessia, Pseudolpidium, Olpidiopsis, Plcotrachelus, 
Ectrogella, Pleolpidmm are parasitic only on lower plants, especially 
on algae. 

SYNCHYTRIACEAE. 

The whole mycelium divides up into a number of sporangia, 
which remain together as a sorus. The winter resting-spores 


1 Woronin, Pringsheim’s Jahrbuch f. wiss. Botanik, 1878 (Fig. 31). 


108 


PHYCOMYCETKS. 


originate from the whole mycelium or parts thereof, and are 
isolated or united into a sorus. 

Synchytrium and Pycnochytrium . 1 

Here, as in Olpidium, the mycelial hyphae are wanting, and the 
vegetative body escapes from the spore as a naked mass of 
plasma, which is later enclosed in a membrane. This vegetative 
body may also develop into a sorus of thin-walled sporangia : 
these separate in water, and each ejects from a pore numerous 
swarm-spores with a single long ciliura. In the event of resting- 
spores being formed, the membrane of the vegetative body 
becomes thickened into a brown exospore. The restiug-spores on 
germination liberate their contents as a single mass, or as several 
zoospores. In the former case the single mass divides at once 
into zoospores, or into a sorus of sporangia, which ultimately 
give off zoospores. 

These fungi are found in the interior of cells, especially of 
the epidermis. The one cell inhabited by the fungus grows 
out as a simple papilla, or several neighbouring cells are also 
modified, and grow out along with the original one to form a 
gall-like swelling. The species of Synchytrium generally in- 
habit the epidermal cells of land plants, yet disease caused 
by them is commoner in moist than in dry situations. They 
cause so slight deformation and damage to cultivated plants that 
they are of little practical importance. 

The Pycnochytrium of De Bary is regarded by Fischer as a 
sub-genus, by Schroeter as a genus. 

Synchytrium. 

The sori of zoosporangia are formed by direct division of 
the mature sporophore, and are enclosed in the colourless 
membrane of the mother-cell. 

Synchytrium taraxaci. De Bary and Wor. (V. S. America). - 
This produces, especially on Taraxacum, warty galls composed of 
a diseased epidermal cell, enlarged and surrounded by a wall of 

'Schroeter: Cohn's BeitrSgt Biol. d. Pflanzen I. , 1 S7.’>, and in Enghr Prantl 
Pflanzenfamilien , 189*2. 

De Bary and Woronin, Bericht. d. nntforsch. Qes. zu Prtilnirii, 1803. 

-We propose to indicate in this way species recorded in Seymour and Fallow's 
“Host-index” for North America; British species hy (Britain). (Edit.) 


SYNCH YTRIU.M. 


109 


less swollen neighbouring epidermal cells. The sporangia contain 
reddish-yellow drops of oil, so that the swellings appear yellow. 
The organs attacked are much 
distorted and more or less 
stunted. 

The same fungus occurs on 
other Compositae, and is pro- 
bably identical with S. san- 
yuineum of Schroeter, which 
produces dark red, crusty swell- 
ings on Cirsium palustre and 
Grepis biennis. 

Along with S. taraxaci one 
often finds Olpidium simulans. 

S. fulgens, Schroeter (U. S. 

America), produces reddish- 
yellow swellings on the leaves 
of Oenothera biennis and 0. 

• . i Fig. 25. — SynchytHum taraxaci. Leaves of 

muriCCLta 5 W 11611 rGStlllg-SpOrGS Taraxacum officinale so deformed by the fungus 
. 1 n -l . that the laminae are all more or less undeveloped. 

appear they form brown crusts, (v. Tubeuf phot.) 

The sori of zoosporangia are 

detached from the host-plant as single sporangia, which 
become scattered over the leaves. 

S. trifolii. Pass. ( = Olpidium trifolii, Schroeter), is as yet 

little known. 

Other American species are : — 

S. papillatum. Pari., on Geranium. 

S. decipiens, Park, on Amphicarpaea. 

S. vaccinii, Thomas, 1 , on Vaccinium, Gaultherict,, Kalmia, 
Rhododendron, etc. 



Pycnochytrium. 

The sori of zoosporangia are not produced directly from the 
mature sporophore, but the contents of the sporophore pass out 
by a fine opening and form a thin-walled vesicle, the protoplasm 
of which breaks up into sporangia. 

Schroeter divides the genus into two sub-genera. 

(A) Mesochytrium. The discharge of the original sporophore 

1 Halsted, “Cranberry gall-fungus”; N. Jersey Agric. Coll. Bullet. 64, Dee. 
18S9. With figures. 



110 


PHYCOMYCETKS. 


and the formation of zoosporangia take place in the cells of the 
living host-plant. In addition, spores are formed which have 
a resting period. 

( B ) Only one kind of spore is formed ; it has a resting period, 
and only proceeds to produce sori of zoosporangia after decay 
of the host-plant. 

(a) Ch rysochytrium : protoplasm contains a yellow oil. 

(h) Leucochytrivm : protoplasm colourless. 

Each of these divisions is sub-divided into forms with simple 
vesicles, and those with compound. 

Mesochytrium. 

Synchytrium (Pycnochytrium) succisae. De Bary and Wor. 1 
This parasite forms warty swellings and yellow spots, generally 



Fio. 26. — Synchytrium succisae. A, A mature sporocarp inside its host-cell. 
B, In the upper part of the cell a sorus of swarm-sporangia after escaping from 
its covering, which lies below it. C t Isolated swarm -sporangium. />, Swarm- 
spores. (After Schroeter.) 


on the radical leaves and base of stem of Scabiosa succisa. 
Infection is brought about in damp situations by means of 
swarm-spores. These have a single cilium, and bore their way 
into the host-cell. After entrance, they produce a plasma-mass, 
which becomes enclosed in a delicate membrane. The cell so 
formed sprouts at its uppermost pole, and gives rise to a new 
spherical cell, into which the older discharges itself. In the 
second cell numerous small sporangia are formed, so that it 
represents a sporangial sorus ; beside it is always found the 
empty membrane of the first cell. The sorus breaks up later 
into single sporangia, which on opening, set free their contents 

'Schroeter, “ Pflansenparasiten aus d. Gattung Synchytrium. ” Colni'x Iltitr. 
Riolog. d. Pflanstn, 1 S7 .*>- 


PYCNOCHYTRIUM. 


Ill 


as zoospores swarming by means of a cilium. In addition, 
resting-spores are developed singly or in groups. 

The first effect on the host-cell of the entrance of a swarm- 
spore is that it becomes distinctly larger. At the same time 
neighbouring cells are so stimulated that they multiply and 
form a prominent ring-shaped swelling. The sporangia discharge 
their zoospores on the host-plant itself, and these pass into 
other cells of the swelling ; here they form resting-spores and 
the host-cells die. Schroeter states that the resting-spores may 
be found from August onwards. 

S. stellariae, Fuck. On Stellaria media and S. nemorum. 
The reddish-yellow hemispherical swellings are produced on leaves, 
stems, flower-stalks, and sepals, either isolated or as a crust. 
The resting-spores generally form brown crusts. The host-leaves 
may be somewhat crumpled, but beyond this undergo little de- 
formation. 1 

Chrysochytrium. 

(1) Forming simple vesicles: 

Synchytrium myosotidis, Kuhn (U. S. America). The epi- 
dermal cells when attacked swell up to form club-shaped 
processes, while the cells with no fungus remain unaltered. 
The normal hairs of the host-plant are fewer on diseased than 
on healthy parts. This parasite attacks Boragineae, cm. Myosotis 
strict a, Lithosjpermuvi arvcnse. 

S. cupulatum, Thomas, produces red eruptions on Potcntilla 
argentea and Dryas octopetala ; diseased cells of the host-plant 
contain red sap. 

S. punctum. Sorokin. On Plantago lanceolata and P. media. 

S. laetum, Schroet. On Gagca. 

(2) Forming compound vesicles : 

S. aureum, Schroet. Attacks many herbaceous plants as well 
as leaves of many shrubs and trees. Frequent on Lysimachia 
Nummular ia, Fvagaria, etc. The cells attacked are swollen and 
enclosed in a patch of enlarged neighbouring cells. 

S. pilificum, Thomas. On Potcntilla Tormentilla. The 
vesicles are hemispherical, and bear on their summits a tuft 
of abnormally elongated hairs. Thomas 2 found this species 

1 Clendeniu (Botanical Gazette, 1S94, p. 296) describes and figures a Synchytrmm 
on Stellaria media in America (Edit,). 

2 Her. d. deutsch. botan. Ges., 18S3, p. 496. 


112 


PHYCOMYCETES. 


on stems, flower-stalks, radical and cauline leaves, and floral 
envelopes. 

Leucochytrium. 

(1) Forming simple vesicles: 

S. punctatum, Schroet. On Gagea pratensis. 

S. rubrocinctum, Magnus, forms little red eruptions on Saxi- 
frage/, grcinulata, the cell-sap of the host-plant becoming red. 

S. alpinum, Thomas. On Viola biflora. 

S. anomalum, Schroet. (U. S. America). On Adorn Moselia- 
trtlina, less common on Ranunculus Ficaria, Isopgrum tJmlictroides 
and Rumcx Acetosa. The size and shape of the swellings, as well 
as of the spores, are very variable. 

(2) Forming compound vesicles: 

S. anemones, De llary and Wor. (U. S. America). On 

Anemone nemorosa, A. ranunculoules and Thalictrum purpura- 



scens, attacking stems, leaves, or flowers, and forming eruptions 
whose cells contain a red sap. In very bad cases, crumpling 
and swelling of attacked organs occur. 


PYCNOCHYTRIUM. 


113 


S. globosum, Schroet. Where the attack is severe, this causes 
pearly swellings or incrustations ; it frequents plants like Viola, 
Galium, Achillea, Sonchus, Mysotis. 

S. mercurialis, Fuck., is very common on Mercurialis pcrennis 
though seldom injurious to it. One severe case is thus de- 
scribed by Schroeter : “In spring the stem of the plant was 
covered by a thick uneven glassy crust, which in course of time 
became raised into wing-like processes running down the stem 
and coated on both sides with white granules of the immature 
parasite ; the leaves were completely rolled together, crumpled, 
and covered with glistening prominences as witli fine silver sand. 
The plant in this condition developed poorly, scarcely flowered, 
and soon died, so that by the end of September few diseased 
examples could be found.” 

CLADOCHYTRIACEAE. 

The vegetative body is frequently a branched mycelium. It 
lives intercellular as a saprophyte, or intracellular as a parasite, 
and forms intercalary or terminal swellings, in which zoospor- 
angia or resting-spores are produced, then it disappears. Sexual 
reproduction does not occur. The parasite lives in and forms 
swellings on aquatic plants, or land plants in moist situations. 
The genera Urophlydis and Pliysoderma contain species parasitic 
on higher plants ; together with the saprophytic Cladosporangium, 
these are regarded by Fischer as sub-genera of Cladochytrium, 
and as such they are also here regarded. 

Urophlydis has both zoosporangia and resting-spores, Physo- 
derma has only resting spores, Cladosporangium only zoospor- 
angia. 

Urophlyctis. 

The delicate mycelium is unbranched, or only slightly 
branched, and lives endophytic, boring through the walls of 
the host-plant. At the place where a hypha enters a host- 
plant it forms a swelling or collecting cell (sammelzell), which 
generally becomes differentiated into a larger cell rich in contents, 
and an outer smaller one with few contents, but with fine 
terminal bristles. From the collecting cells new hyphae 
originate and produce other collecting cells in neighbouring 
host-cells. The zoosporangia are situated outside the host-cells, 

H 


114 


PHYCOMYCETES. 


but send a hyphal process inside, which branches into a tuft 
of rhizoids. Resting-spores may be found, several in each cell. 

Cladochytrium (Urophlyctis) pulposum, (Wallr.), causes on 
leaves, stems, and Mowers of Chenopoclium and Atriplex glassy 
swellings, in the undermost cells of which are situated the 
zoosporangia. The resting- spores have brown shining walls and 
lie inside the cells. The zoospores are uniciliate. 

Cl. (Ur.) butomi, Biisgen. On leaves of Butomus umbellatus. 
Black spores are produced containing resting-spores. The col- 
lecting cells have tufts of hair. 

Physoderma. 

Zoosporangia are absent. Resting-spores formed, several in 
each host-cell. 

Cladochytrium (Phy.) menyanthis, De Bary (U. S. America). 

( )n leaves and petioles of Menyantlies trifoliata this forms 
vesicles containing resting-spores. The collecting cells have 
terminal hair-tufts. Diseased leaves are generally smaller than 
healthy. 

Cl. (Phys.) flammulae. Biisgen, forms little swellings on 
leaves of Ranunculus Flammula. 

Cl. (Phys.) Kriegerianum, Magnus, causes transparent swell- 
ings on Carvm Carui. 

Cl. (Phys.) iridis, De Bary, on Iris pseudacorus. 

Fischer mentions other species on Scirpus, Alisma, Ranunculus, 
Potentilla anserina, Silaus pratensis, Siam latifolium, Phalnris, 
Glycerin, Symphytum, Mentha, Rumcx, Allium, etc. 

Brunet 1 describes Cladochytrium viticolum as the cause 
of the much-discussed Brunisure of vine : also Cl. mori as a 
new disease of the mulberry . 2 

The same authority :i designates as Pyroctonum sphaericum, a parasite on 
wheat, which lias become very abundant in Southern France. 


(2) ZYGOMYCETES. 

Unicellular fungi. Sexual reproduction does not take place by 
the fertilization of an ovum in an oogonium by an antheridium, 

1 Prunet, Compt. rend., 1894. - Prunet, Conipt, rend., e\x., 1895, p. 222. 

:l Prunet, Compt. rend., 1894, n., p. 108. 


ZYGOMYCETES. 


115 


but by conjugation or union of two cells of the mycelium 
.separated off from the ends of two hyphae by transverse walls. 
As a result of conjugation, a zygospore is produced, which is 
a resting-spore and corresponds to the oospore of the Oomycetes. 
The zygospore puts forth a germ-tube, which becomes a mycelium 
bearing sporangia on sporangiophores. From each sporangium, 
spores, never swarm-spores, are set free, germinate, and produce 
a mycelium. Sporangia similar in form to the zygospores may 
be asexually produced on the mycelium. The unicellular and 
much-branched mycelium grows into its substratum, and is 
nourished as a rule saprophytically. The Entomophthoreae cause 
important insect-diseases on Muscidae, Cabbage Butterflies, and 
caterpillars of Trachea piniperda (the Pine Beauty). 

Another common group of the Zygomycetes, the Mucorini, 
penetrate into bruised places in living fruits, and produce decay 
(see p. 180). Some other Zygomycetes are parasitic on fungi 
(Conidiobolus), some on animals. 

(3) OOMYCETES. 

These fungi possess a one-celled and much-branched mycelium. 
In their vegetative structure they most nearly resemble algae 
like Vaucheria. Reproduction is brought about, asexually by 
means of swarm-spores formed in sporangia (conidia also occur) ; 
sexually by oospores derived from oogonia and antheridia. 

There are three families of Oomycetes : Saprolegniaceae, Mono- 
blephnrideae and Peronosporeae. Two of these groups contain 
parasitic forms : Saprolegniaceae ( c.g . Achyla prolifera, dangerous 
to Fish and Crustaceans) ; and Peronosporeae. 

PERONOSPOREAE. 

The greater number of the Peronosporeae live as parasites in 
the tissues of higher plants, and obtain nourishment generally by 
means of haustoria. The mycelium, in earlier life at least, has no 
dividing septa, and generally grows in the intercellular spaces of 
the host-plant, and sends haustoria into the cells. Reproduction 
is effected asexually by formation of swarm-spores in sporangia, 
and sexually by means of oospores. The latter are produced 
from the fertilization of an ovum in an oogonium by an antheridium 
whose contents pass through a fertilization-tube penetrating the 


116 


PHYCOMYCETES. 


oogonium wall . 1 No formation of spennatozoids occurs, as is the 
case in Vauclieria and other groups of algae showing close rela- 
tionship to these fungi. In certain cases the formation of 
swarm-spores in sporangia does not take place, but conidia 
are produced, which germinate directly into a mycelium. 

Preventive measures against the whole group consist in 
destruction (by burying or burning) of diseased and dead parts of 
host-plants which contain the hibernating oospores ; by change of 
crop on infected fields ; and by treatment with copper reagents 
(see Chap. VI.). 

To the Peronosporeae belong the genera Pythium, Phytoph- 
thora, Cystopus, Basidiophora, Plasmopara, Sclerospora, Premia and 
Peronospora. 

Pythium. 

The mycelium possesses no haustoria, and grows both between 
the host-cells and inside them. Cross-septa are not present at 
first, but later these may be found at irregular intervals. 
Pythium lives as a parasite in living plants, or as a saprophyte 
on a dead substratum. The conidia are of various forms, and 
either germinate directly into hyphal filaments, or discharge their 
contents into a bladder where zoospores are developed and 
liberated as free-swimming spores with two lateral cilia. The 
oogonia contain only one ovum-cell, which is fertilized by means 
of an antheridial tube applied to the oogonium. The thick- 
walled oogonia on germination produce hyphae or discharge zoo- 
spores. 

Pythium de Baryanum. Hesse 2 (Britain and U. .S. America). 
This parasite is injurious to the seedlings of various plants in 
gardens and fields. Some of its commoner hosts are maize, 
clover, mangel, millet, and many species of the Cruciferae ; it has 
also been found on the prothalli of JSqumctum and Lycopodium? 
It may also attack living or dead leaves and tubers of potato. 

The sporangia have a lateral beak-like outgrowth, into which 
the plasma passes and divides into biciliate zoospores. The 

‘In many species the fertilization -tube remains closed (.</. Plasmopara 
viticota. 

-Hesse, Pythium de Baryanum, Halle, 1874 . Atkinson (Conn II Unit). A yrie. 
Expt. Mat., Bull. ! 14 , 1895), describes and figures t hi- and other fungi causing 
“ Damping-off.” (Edit.) 

:l Sadeheck, Nalurforsch.- Vtcsammluny., lS7t>. 


PYTHIUM. 


117 


sporangia, however, may hrst pass through a resting period. 
Sexual reproduction consists in the impregnation of an egg-cell 
by means of a fertilization-tube from an antheridium. The 
oospores are formed singly in each oogonium, and are liberated 
only after decay of the oogonium walls and the tissues of the 
host- plant containing them. After a resting period they pro- 
duce a germ-tube, which penetrates into the host-plant and 
becomes a delicate branched colourless intercellular mycelium. 
Hibernation is accomplished both by these oospores and by resting- 
conidia, which remain amongst the decaying plant-debris on the 
ground. 

Humphrey has observed sickness and death of cucumber 
seedlings as a result of Py. de Baryanum. Wittmack found a 
species {Py. Sculebeckiamim) very destructive on peas and lupines 1 
in various localities ; it has been observed frequently since. 

Py. gracile is parasitic on algae. 

Py. dictyospermum, Rac. occurs in Spirogyra. 

Py. cystosiphon is found on species of Lemna. 

Py. intermedium frequents protlialli of vascular cryptogams. 


Phytophthora. 

The mycelium is at first non-septate though much branched. 
It grows both between and through the host-cells, and in some 
species, {c.g. Ph. omnivora), has small haustoria. 

The conidiophores branch and produce a large number of conidia 
or sporangia in succession. The first conidia are terminal, but 
are displaced towards one side and thrown off by further 
growth of the conidiophore to produce other conidia. 

The sporangia distribute their contents as swarming cells with 
two lateral cilia ; the conidia produce a hypha directly. The 
egg-cells are developed one in each oogonium, and are fertilized 
by an antheridium. The spherical oospores germinate in spring 
by means of a germ-tube. 

Phytophthora omnivora, De Bary 2 (syn. Ph. fagi, R Hartig.) 
This is a destructive enemy to the seedlings of conifers, and even 
more deadly amongst naturally-sown beech-seedlings. Death of 
the beech is preceded by brown-spotting of stems, cotyledons and 

1 Verein z. Bef. d. Moorkultur, 1891. 

- R. Hartig, Zeitschrift f. For at u. Jcigd-wesen 1875; also, Untersuchungen mix 
d. forstbotan. Inst. Miinchens, 1880. 


118 


PHYCOMYCETES. 



first leaflets. The disease is spread during summer by conidia. 


or swarming cells produced from 


Flo. 28 . — Phytophlhora omnivor a. Cotyledons 
and primary leaves in early stage of attack ; 
the dise.'ise forms brown 8jM»ts where patches 
of mycelium are developed. J natural sice, 
(v. Tubeuf del.) 


sporangia. The passage through 
winter is effected by means of 
oospores, resulting from fertiliza- 
tion of an ovum in the oogonium 
by a fertilization-tube from an 
antheridium. The intercellular 
mycelium is at first nonseptate r 
later septate, and forms small 
haustoria. Seedlings of other 
plants, besides those already 
mentioned, and also succulents 
(c.(j. Sevipervivum and Cactus) 
may be attacked and killed by 
this same fungus. 

This epidemic cannot well be 
combated except by methods 
applicable only in the nursery. 
The most effective method is to 
plant no young seedlings in 
plots which have already been 
diseased, but to reserve such 
plots for older plants to which 
the fungus is not dangerous. If 
the disease be not very general, 
attacked plants may be removed 
singly and destroyed. Since 
moist air is very favourable 
to distribution of the disease, 
all nettings or trellises should 
be removed from seed-beds 
threatened by attack. In dry 
airy localities there is less- 
danger to seedlings than in 
moist. 


The fungus often appears- 
in such force that seed-beds of beech or conifers are denuded 
of every plant within a few days, and in the forest beech- 
seedlings may, during damp weather, be completely exterminated 
over great areas. 


PHYTOPHTHORA. 


119 


Another parasite of conifer seedlings — Fusoma parasiticum — 
which somewhat resembles Phytophthora, is figured and described 
amongst the “ Fungi imperfecti.” 

Phytophthora infestans, I)e Bary. 1 This parasite was first 
observed in Europe in 1845, and has since then become 



Fig. 29. 


Fig. 30. 



Fig. 29.— Cellular tissue from diseased cotyledon of Beech. The starch-grains 
have been absorbed from the cell-protoplasm which has shrunk away from the 
cell-wall a ; 6, b, intercellular fungal hyphae with very tiny haustoria ; c, c, 
fertilized oogonia, each containing a single oospore. (After K. Hartig.) 

Fig. 30 .—Phytophthora omnivorci on the epidermis of a Beech-cotyledon, o. 
Outer wall of epidermal cell ; b, cuticle ; c, hyphae growing between cell-wall 
and cuticle, causing the slight protuberance d ; e, spot where a hypha has 
emerged through the cuticle and developed as a sporangiophore/; after the first 
sporangium has reached maturity a second begins to form, g and h, whereby the 
first is displaced ; A-, a stoma from which sporangiophores have developed. 
(After R. Hartig.) 


only too well known. It attacks leaves, shoots, and tubers 
of potato and other Solanaceae, e.y. the tomato ( S. . Lycopersicum). 
The potato leaves become discoloured, brown-spotted, and 
crumpled, especially in damp weather. The sporangiophores 
(gonidiophores of Pe Bary) issue from the stomata in 

1 De Bary, Journal of Botany, 1876, and Journal of the Royal Agrir. Society, 

1876. 


120 


PHYCOMYCETES. 


tufts, and form a white border round the brown parts of 
the leaf ; they are monopodially branched and produce terminal 
sporangia (gonidia), which are easily detached. The sporangia 

on germination either pro- 
duce a varying number of 
zoospores, or germinate 
directly like conidia to form 
a mycelium capable of pro- 
ducing new conidia. The 
potato -disease is distin- 
guished from Phytophthora 
omnivora in the absence 
of sexual reproduction by 
oospores . 1 It is generally 
assumed that the mycelium 
hibernates in potato-tubers, 
from which the fungus 
recommences to spread in 
spring. Boehm , 2 however, 
contests this, and holds the 
hibernation of the fungus 
to be quite unknown, and 
that from the tubers of 
a diseased plant, either a 
healthy plant or none at 
all results. 

The Phytophthora potato- 
disease is quite distinct from 
{a) the potato-blight or wet-rot which, according to Boehm, is the 
result of closing up of the lenticels, with a consequent stoppage 
of respiration ; (h) bacteriosis, which will be considered amongst 
the bacterial diseases of plants. 

Lagerheim 3 has pointed out that Solanum nutrient inn 
much cultivated in Ecuador on account of its edible fruit, has 
been for many years subject to attack from Phytophthora 
infestans ; the fruits sicken and rot off before ripening. The 

1 This is a well-known point of controversy, for an interesting discussion of 
which we would refer to “ Di*ca*es of crop*,” Worth. (1. Smith, 1SS4. (Edit.) 

2 Boehm, Sitzungsber. d. Zool.-botan, Or*. , Vienna, 1892. 

3 Rivista Ecuatoriana, 1891. 



Fig. 31. — Surface of a Beech-seedling with swarm- 
spores a, '> ; the germ-tubes from these penetrate 
between adjacent epidermal cells ; c, sporangium with 
zoospores already germinating inside it, rf, /; e, a 
germ-tube which pas penetrated directly into an 
epidermal cell ; g, germ-tube which, after growing 
for a time inside a cell, has again made its way out. 
(After R. Hartig.) 



Fig. 32 . — Pkytophthom in/estaas. The Potato disease. A, Potato leaf with 
brown spots and white patches of fungi on the lower side. J9, Groups of conidio- 
phores emerging from a stoma close beside a hair of the potato leaf. C, Conidio- 
phores and eonidia, much enlarged. D , Leaf of potato much shrivelled up and 
brown, as in the laier stages of the disease, (v. Tubeuf del.) 




122 


PHYCOMYCETES. 


same author also quotes the disease on Solcinum cariprnse 
at Quito, and on Petunia hybrida at Upsala. 

The potato disease is above all an associate of moist 
weather. In such circumstances, the conidia are produced 
very rapidly and the zoospores readily distribute themselves in 
the moist soil. There is thus greater risk to the potato crops 
on wet soils. 

For wintering, potatoes as healthy as possible should be chosen. 
This is particularly the case if the tubers are required as seed : 
for the fungus-mycelium spreads from the tuber into the shoot. 
Whole tubers are less liable to infection than those cut or 
broken. Some varieties (e.y. thick-skinned) are less easily 
infected than others ; such should be selected and bred. 

As a preventive measure the leaves may be sprayed with 
Bordeaux mixture, or with a copper carbonate mixture. 1 By 
these means conidia and zoospores which alight on the plants, 
are killed and their germination prevented. The leaves them- 
selves remain uninjured if the copper compound be used dilute 
enough. These compounds may even be beneficial to the growth 
of the host-plant, as was found by Kumm 2 for the vine, and 
Frank and Kruger 3 for the potato. 

Frank and Kriiger found on using a two per cent, copper 
sulphate and lime mixture, in which the copper is known to be 
the potent constituent, that the potato leaves were stronger, their 
chlorophyll-contents greater, their power of assimilation and 
transpiration was increased, the life of the leaf was lengthened, 
and the yield and starch-contents of the tubers were increased. 
They regard the effect of the copper on the leaf as the result of 
a ehemotaxic stimulus. 

Jensen recommends disinfection of seed-potatoes by heating 
at 40 C. for four hours. 

Ph. phaseoli, Thaxter, lives in young bean-pods and causes 
them to shrivel up. The fungus is as yet incompletely known, 
having only been observed in America where Thaxter 4 reports 
great destruction of Lima bean (Phascolus hniatus) near New 
Haven. 

'See .also § 12. Detailed experiments of this kind are frequently described 
in the magazines relating to agriculture. (Edit.) 

2 Ber. d. deutech. botan. Oe*., 1891), p. 189. 

3 Ber. d. deulsch. botan. Oes., 1894, p. 8. 

4 Thaxter, Botanical Gazette , 1889. 


CYSTOPUS. 


123 



Cystopus (Albugo). 

The mycelium is branched and grows between the cells ot 
living plants, obtaining its nourishment by means of haustoria. 
The conidial cushions rupture the epidermis of the host. 1 he 
conidia or sporangia are smooth-coated, and are produced 
acropetally in chains on short stalks from which they fall off 
separately when ripe. The sporangia germinate and discharge 


Fig. 33. — Cystopus candidus on plants of Capsella bursa 'pastoris. The fungus 
has caused distortion and thickening ; the white porcellanous conidial cushions 
shew up distinctly on the dark background, (v. Tubeuf phot.) 


swarming spores with two unequal lateral cilia. The egg-cells, 
produced singly in each oogonium, are fertilized by an antheridium. 
The thick-walled oospores remain enclosed in the intercellular 
spaces of the host-tissue, and on germinating in spring discharge 
swarming spores. 

Cystopus candidus (Pers.) Lev. White Rust. This fungus 



124 


I*HY COM YCETES. 


is very frequent on wild and cultivated Cruciferae throughout 
the whole world, and causes deformation of shoot, leaf, and flower. 




Fio. 34. — Cp slop us candidun. B, Conidiophores isolated from the cushion ; the 
conidia or sporangia are united by intermediate cells. C , Sporangia breaking up 
to form swarm-spores. D, Swarm-spores escaping. E , Swarm-spores in motile 
condition. F, Swarm-spores come to rest and germinating. G, Two gerin-tubes 
entering a stoma of Ltpidium sativum ; the stoma is shown from the inside, so 
that the spores from which the germ-tube* arise are on the outer surface and 
unseen. (After I)e Bary.) 



Fin. 35. — Flower of Radish ( Rnphanu s salivas) hypertrophied by Cystopus 
Candidas. The much enlarged ovary stands out in the centre. The anthers are 
lraf-like ; the |>etals are much enlarged and hang downwards; the sepals art* 
somewhat enlarged. (Specimen from Botanical Museum of Brlangcn, and 
photographed by Dr. Bruns.) 


The conidial cushions form thick white stripes with a porcellaneous 
appearance, by which they are easily distinguished from the 
cushions of Peronospora parasitica often present on the same plant. 



CY STOP US. 


125 


Besides conidia, spherical oospores may also be present ; these 
are generally produced on the stems of the host-plant, but also 
on flower-stalks and ovary-walls. 

The spherical conidia arise in simple chains on short coni- 
diophores, and are loosely connected by tiny intermediate cells. 
The conidial cushions rupture the epidermis and the ripe conidia 
fall off to produce biciliate swarming cells (Fig. 34). These 
give rise to germ-tubes which enter the stomata of seedlings and 



Fig. 36. — Flower of Eadish hypertrophied by Cystopv.s candidvs. The white 
swollen conidial cushions occupy the enlarged petals, sepals and ovaries. (Dr. 
Bruns’ phot.) 


develop to intercellular mycelia, fine short lateral twigs of 
which pierce the wall of the host-cells and become little 
spherical haustoria. 

The oogonia arise as thick-walled spherical swellings on the 
mycelium. The antheridium, after applying itself to the oogonium, 
widens and projects a fine fertilization-tube through the wall to 
the egg-cell. After fertilization is effected, the egg-cell is enclosed 
in a firm uneven membrane, and hibernates inside the oogonium. 
In spring the plasma of the oospore forms numerous biciliate 






l’HYCOMYCETES. 



swarm-spores which escape from the enclosing coats and germinate 

on seedling plants. 

De Bary 1 found germ-tubes of 
Cystopus entering all the stomata of 
Lepidium sativum and of Capsella, 
but they only developed further if 
the part attacked were the cotyledons. 

Magnus 2 observed an infection of 
Raphanus Raphanistrum in which the 
unopened buds were infected by swarm- 
spores. Oogonia may be found in the 
flowers of this same plant, whereas 
conidia alone only are present in 
Capsella. 

White rust is most commonly 
observed on Capsella, causing slight 
local swelling or marked hypertrophy. 
It is also found to injure radish 
(Raphanus sativus), horse radish 
( Coehlearia armoracia), cress ( Lepidium, 
sativum), species of cabbage and 
turnip (Brassica Napus, B. nigra, B. 
Rapa, B. olcracea), wall- flower ( Cheir - 
anth us Cheiri), water cress (Nasturtium 
amphihium, etc.), caper-plant (Capparis 
spinosa), and other wild and culti- 
vated plants belonging to, or closely 
allied to the Cruciferae. 

Wakker 3 investigated the changes 
brought about on a number of Cruci- 
ferae by Cystopus. Some plants showed 
little or no deformation or anatomical 
alteration, others showed much. While 
the anatomical changes in the various 
species examined agreed in general, 
yet some showed a predominant or 
exclusive formation of conidia, others of oospores. The changes 


Fig. 37. — Cystopu* portidacac , I). C. 
j/t, mycelium ; /, hasidia ; c, aporca 
with intermediate cella. (After 
Tulasne.) 


1 Morphology and Biology of the Fungi. English Edition. 
- Abhmid. d. hot an. I '(reins d. Prov. Brandenburg, xxxv. 
' Pringsheim’ 8 Jnhrlmch, 1S92. 


CYSTOPUS. 


127 


«3T; 


observed on Capsella may be summarized here : the fungus 
attacks all parts above ground, and causes enlargement of 
parenchymatous cells ; it forms only 
conidia ; formation of chlorophyll is 
increased ; the formation of interfasci- 
cular cambium is diminished or altogether 
suppressed ; the intrafascicular cambium 
retains its activity longer ; accessory 
vascular bundles make their appearance ; 
no differentiation of tissue takes place 
in the ovary wall, the secondary vessels remain incomplete, 
and the embryo dries up. 



Fig. 3S. — Germinating spores of 
Cystopus portulacae. (After Tulasne.) 


C. portulacae, D. C. On Portulaca oleracea and sativa (U. S. America). 

C. tragopogonis, Pers. 1 (C. spinulosus ) (Britain and U. S. America). On 
Gompositae, e.g. Chamomilla, Achillea, Cirsium, Scorzonera, etc. The markings 
on the spore-coat take the form of a double net-work. 

C. convolvulacearum, Otth. ( C. . ipomoeae-panduranae, Farl.). On Con- 
voloulaceae. (Halsted 2 gives this as one of the causes of rot in sweet potato 
in America.) 

C. bliti (Biv.-Bern.). On species of Amarantaceae (U. S. America). 

C. lepigoni, de Bary. On Spergularia (Britain). 


Basidiophora. 

The non-septate mycelium inhabits intercellular spaces of 
living plants, and is nourished by small haustoria. The conidio- 
phores issue in tufts from the stomata, and have a characteristic 
form ; they are unbranched with club-shaped ends, from which 
arise several sterigina-like conidiophores with almost spherical 
conidia. The conidia or sporangia are produced in large numbers, 
and on germination discharge numerous zoospores with two 
lateral cilia. The oospores are formed singly in the oogonia, and 
appear as yellowish-brown bodies in the interior of the plant. 

Basidiophora entospora, Eoze and Cornu. On Erigeron cana- 
dense, Aster, Solidago, etc. (Britain and U. S. America). 


Plasmopara. 

The mycelium is richly branched and grows intercellular, 
nourished by little button-shaped haustoria. The conidiophores 

1 Magnus, Ber. d. deutsch. botan. G'es . , 1893. 

2 Zeitsrhrift /. Pflanzenkran the iten , 1895, p. 338. 


128 


PHYCOMYCETES. 


arise in tufts from the stomata ; they are branched in various 
ways, and from each branchlet a single conidium is abjointed. 
The contents of the conidia emerge as swarming cells with two 
lateral cilia, or as vesicles which emit a germ-tube. The egg-cells 
occur singly in each oogonium, and are fertilized by an antheridium. 
The oospores remain long enclosed in the thick-walled oogonium. 



Fio. lW.—Pta*mopara viticola , Vine leaf with white spots on the under surface, 
from which tufts of conidiophores emerge, (v. Tubeuf del.) 


Plasmopara nivea (I'nger). (Britain and 1 S. America). 
IuHicts great injury on various wild and cultivated Umbelliferae, 
r.g. carrot (Dnucus Carota ), parsley ( Pctroscliauw satinnn), chervil 
( A nth riscus Ccrefol in m ). 

Plasmopara viticola. Berk. 1 The Downy or False Mildew of 

1 Bibliography. IK- Bury, Anna!, d. «ri. tint., 1863. Viala, Dit Pilzt d. 
\Y< instorkex ; with g<x)<t bibliography. Prillieux, Anna!. <!• . I'inslit. nat. 
ai/ronomiijtu , 1881. Cornu, In /’« rouoK/wra dt » Viijms, Paris, 188'J. Sajo, 


PLASMOPARA. 


129 


the Vine. This parasite was introduced into Europe from 
America . 1 It makes its appearance in early summer as white 
patches on the under surfaces of leaves, sometimes also on stalks 
and fruit. In the course of the summer the leaves show brown 
spots and dry up. 

The white patches consist of tufts of branched conidiophores, 
from which ovoid conidia are abjointed. These on germina- 



Fig. 40 . — Plasmopara viticola. Conidiophores, much enlarged, (v. Tubeuf del.) 


tion in rain-drops discharge six to eight swarming cells from 
which germ-tubes grow into the epidermis of the host-plant ; 
thus the disease spreads rapidly during moist weather and a 

Peronospora viticola, 1S90. Magnus, Witt mark’s Gartenzeit, 18S3. Scribner, 
Report of U.S. Dept, of Agriculture for 1SS6, pp. 96-105; this contains an 
excellent account of this mildew. Articles on this subject dealing with remedial 
measures are frequently published in the U.S. Amer. Department reports and 
bulletins, in the bulletins from experimental stations, and in the horticultural 
journals. 

1 Seymour and Fallow give it as occuring on every American species of ]"/is. 

I 


130 


PHYCOMYCETES. 


wet season is very favourable to it. The mycelium is non- 
septate and spreads through the intercellular spaces of the host, 
nourished by button-like haustoria sunk into the host-cells. 
The antheridium comes into contact with the oogonium by a 
fertilization tube, which, however, remains closed. The oospores 
hibernate in leaves and fruit. 

Prevention } Ammoniacal copper carbonate solution, eau 
celeste, or Bordeaux mixture, prepared as described on p. 69, 
may be used. The first-named solution seems least liable to 
injure the foliage ; the others must, on this account, be used 
with care. The first application is made about the time the 



Fig. 41. — Plasmopara pf/f/maea on Anemone nanoroaa. Conidiophores emerging 
from a stoma. Intercellular mycelium with haustoria. (v. Tubcuf del.) 

berries are well formed, and the sprayings are repeated every 
twelve to fifteen days, or oftener if there are heavy rains, till the 
grapes begin to colour. It must, however, be remembered that 
sprayings of this kind do not reach the mycelium inside the leaf, 
but only act superficially, killing any developing conidiophores 
or conidia which may alight on the leaf. These fungicides are, 
at the same time, remedies for powdery mildew ( Uncinula). 

“ Sulphuring” as a remedy for this and the powdery mildew 
has been recommended by continental writers. 2 The burning 
of all diseased vine-leaves is strongly recommended. Attention 
also should be given to the cultivation of disease-proof varieties. 3 

PI. pygmaea (Unger). On Ranunculaceae (Britain and U.S. America). 

PI. pusilla (De Bary). On Geraniums. 

•Galloway, “Fungous diseases of the grape and their treatment,” U. S. 
Dept, of Ai/ric., Farmers' Bulletin, No. 4, 1881. 

-Oesterr. Weinbaukongress, 1891. Reported in Oest. landwirtk. Wochenblatt, 
x., 1881. 

11 Millardet (see Chap. VI.) 


PLASMOPARA. 


131 


PI. viburni, Peck. On Viburnum (U.S. America). 

PI. densa (Rabli.). On Scropliularineae (Britain). 

PI. ribicola (Sehroet.). On Ribes rubrum (U.S. America). 

PI. epilobii (Rabh.). On Epilobium palustre, and E. parvifolium. 

PI. obducens (Sehroet.). On cotyledons of Impatiens (U.S. America). 
PI. geranii (Peck.). On Geraniums in America. 

PI. Halstedii, Berl. and de Toni. On Silphium, Rudbeckia, Heliantlius , 
and many other American Compositae. 


Sclerospora. 

Mycelium intercellular in living plant-tissues, and deriving 
nourishment by means of haustoria. The conidiophores are 
thick, short, and divide at their apices into short broad branches, 
from each of which a single conidium is abjointed. The conidia 
in germinating discharge swarming cells. One oospore is formed 
in each oogonium. 

Sclerospora graminicola (Sacc.) lives in several species of 
Setaria (U.S. America). 

Bremia. 

Mycelium intercellular in higher plants, and nourished by 
little button-like haustoria. 
and at their apical ends 
become swollen in a char- 
acteristic manner, so as to 
resemble a hand field cup- 
like with the fingers project- 
ing separately upwards, like 
the tentacles of Hydra. The 
conidia are abjointed singly 
from the tentacle-like pro- 
cesses, and germinate, emit- 
ting a germ-tube through a 
definite thin spot in their 
coat. Oospores originate 
singly in oogonia. 

Bremia lactucae, Beg. 

( Peronospora ganglioniformis 
Berk. 1 ) (Britain and U.S. America). The richly-branched conidio- 
phoi’es appear singly on attacked parts of plants. This fungus 
’Cornu, Compt. rend., 1878. 


The conidiophores are branched, 



132 


PHYCOMYCETES. 


may cause considerable damage to the lettuce (Lactuca sativa), 
this being especially the case in France. The parasite is most 
dangerous in forcing-houses during winter or early spring, and 
spreads rapidly, favoured by the damp atmosphere. The young 
diseased plants are stunted, and take on a pale colour. Early 
removal and destruction of diseased plants is to be recommended; 
also abandonment for lettuce-cultivation of infected houses or 
frames. 

In addition to lettuce, this fungus attacks a number of 
Compositae, e.g. Cineraria, Sonchus, etc. 

Peronospora. 

The mycelium is intercellular in living plants. The haustoria 
may be simple, button-shaped, or thread-like, or may branch 
inside the host-cell. The long and much-branched conidiophores 
produce conidia singly at the ends of their branches. The 
conidia produce a germ-tube. The oospores are brown-coated 
and are formed singly in the oogonia ; they germinate in spring. 

Peronospora Schachtii, Fuck. 1 is injurious to the inner 
leaves of sugar beet and mangold (Beta vulgaris), while young 
seedlings are killed by it. The mycelium hibernates in the 
roots ; as yet oospores have not been found. 

P. effusa (Grev.) This causes injury to spinach (Sjnnacia) 
oleracea) and other Chenopodiaceae (Britain and U.S. America). 

P Schleideni, Ung. Kills the leaves of cultivated and wild 
species of onion ( Allium ) (Britain and U.S. America). 

P dipsaci, Tub Injures stems and leaves of Dipsacu sylir.sfer 
and D. Fullonum. 

P knautiae. Fuck., of Knautia and Scabiosa, is probably identi- 
cal with last. 

P viciae (Berk.) (Britain and U.S. America). A dangerous 
species to many l’apilionaceae (especially peas, beans, tares, 
lentils, etc.), often causing great damage to field crops. In 
recent years the new fodder-plant Lathyrus .sylvc.sfrix has been 
frequently attacked. 2 

P. trifoliorum. De Bary a (Britain and l .S. America). 1 >is- 
tinguished from the preceding form by its irregularly marked 

’Kllhn, Botan. Zritung, 1873. 

2 Zeitschrift f. Pjlan~enkrankhtitrn, 1 1 . , jt. 225 and 28.'!. 

3 Smith, Diseases of Crops, I.oiu Ion, 1 SSI. 


PERONOSPORA. 


133 


oospore-coat (oospores of P. viciae have a coat with a regular net- 
work). It occurs on steins, leaves, and petioles of clovers, lucerne 
and other Papilionaceae, often with disastrous effect. 

P. sparsa, Berk. (Britain and U.S. America). This parasite 
on the rose was first observed in England. It injures indoor 
roses, causing a fall of the leaf, preceded by the appearance of 
lilac-coloured spots which, on the underside of the leaf, are closely 
beset with a white coating of conidiophores . 1 



Fig. 43 . — Peronospora viciae. Conidiophores and conidia. (v. Tubeuf del.) 


P. arborescens (Berk.). On leaves and shoots of wild and 
cultivated poppies ; especially injurious to seedlings of garden 
species. 

P. parasitica (Pers.) (Britain and U.S. America). This pro- 
duces greater or less deformation of attacked stems of many wild 
and cultivated Cruciferae. Amongst cultivated plants the most 
liable to injury are the varieties of turnips and cabbage, radish, 
rape, cress, wallflower, also the mignonette. It is generally found 
along with Cystopus canclidus on shepherd’s purse ( Capsella ). 

P. cytisi, Rostr ., 2 attacks seedlings of laburnum in Denmark, 
causing death in a few days. The leaves become brown spotted, 

1 Zeitschri/t f. P.-Tcrank., n., p. 386, (description of attack in Silesia.) 

- Rostrup, Zeitschrift f. Pflanzenhrankheiten , 1892. 

Magnus, Ueclivigia, 1892. 


134 , 


PHYCOMYCETES. 


and branched conidiophores with light-brown conidia arise from 
their underside. Numerous oospores may be found in the leaves. 
Kirchner 1 observed the disease on leaves of four-year-old plants, 
yet without injurious effects. 

The following are other British or American species: 


Peronospora ficariae. Till. On Ranunculus*, Myosurus , etc. 

P. corydalis, De By. On Cory dolls and Dicentra. 

P. violae, De By. On Viola tricolor. 

P. arenariae var. macrospora, Farl. On ,$ 'dene. 

P. alsinearum, Casp. On Cerastium. 

P. claytoniae, Farl. On Claylonia. 

P. lini, Schroet. On Linum. 

P. potentillae, De By. On Rosaceae e.g. Geum, Fragaria, and Potent dl a. 
P. Arthuri, Farl. On Oenothera. 


b 



Fio 44 —Pcronotpora altinearum. Sexual orjan*. n. ^ mmg condition ; h, for- 
mation of ovum and fertilization-tube ; c, after fertilization, (periplism some- 
what contracted by preparation, and the fertilization-tube unusually thick), 
w, antheridium ; ©, oogonium. X 350. (After l)e Bary.) 


P. leptosperma. De By. On Compositae e.g. Artemisia. 

P. Candida, Fuck. On A ndrosacc and other Primulaceae. 

P. cynoglossi, Burrill. On Cynoglossttm. 

P. myosotidis, De By. On Myosotis and Echinospermnm. 

P. sordida. Berk. On Nicotiana and Scrophularia. 

P. hyoscyami, D. By. On Tobacco in America and Australia (Gun/. 
Chron. ix.). 

P. linariae. Fckl. On Linaria. 

P. grisea, Ung. On Veronica „ 

P. lophanti, Farl. On Lophanthus. 

P. alta, Fckl. On Plantago. 

P. (Plasmopara) cubensis is reported- as causing an extensive and 
destructive disease of cucumbers ( Cucumis and Cucurbtta). 

P. (Plasmopara) australis, Speg. On Ec/u nocyst is lobata and Sicyos 

angulatus in America. 

'Kirchner, Zeilschrift /. Pflanzenkraulhiittn, 1892. 

2 Humphrey, Report of the Mass. Agric. 2uy>er._ Slat., 1890-92. 

Massee, Gardener’s Chronicle, Vol. XVII., p. 6.»G, 1895. 


HIGHER FUNGI. 


135 


P. oxybaphi, Ell. and Kell. On various Nyctaginaceae. 

P. polygoni, Tlnim. On Polygonum. 

P. euphorbiae, Fuck. On Euphorbia. 

P. urticae (Lib.). On Urticaceae. 

P. elliptica causes death of lilies. 1 

B. Higher Fungi (Mycomycetes). 

The higher fungi are distinguished from the lower in possessing 
a mycelium, which, from the first, is divided by means of cross- 
septa. The mycelium of the lower fungi, though often much 
branched, remains unicellular till cross-septa arise on formation of 
reproductive organs or in the older stages of the fungus . 2 In 
higher fungi, septation begins with the first appearance of 
mycelium and extends acropetally, growth in length proceeding 
from the terminal cell. Sexual organs are without doubt present 
in the lower fungi, but amongst the higher forms, Brefeld believes 
that the sexual act no longer exists. On the other hand, certain 
organs, found especially in the lichens, have been regarded as 
sexual. 

Dangeard regards the union of cell-nuclei as a sexual act, 
and assumes its existence in the asci and basidia of higher 
fungi. His more recent investigations on the nuclei of fungi, 
combined with those of Pairault and Eaciborski, have laid the 
way to a new systematic arrangement . 3 Just as amongst the 
lower fungi the cell produced by a sexual act contains a nucleus 
derived from the fusion of two nuclei of distinct origin, so amongst 
the higher fungi one also finds cell-nuclei derived from copulation. 
The investigations of Dangeard, Ilosen, Wager, Pairault, and 
Eaciborski, lead to the conclusion that : 4 “a stage may be 
found amongst higher, as well as lower fungi, in which two 
cell-nuclei of one cell copulate. The cells known as oospores 
of the Oomycetes, zygospores of the Archimycetes and Zygomycetes, 
chlamydospores of the Ustilagincae, and teleutospores of the 

'Smith, Disease of Lilies, 188S. 

2 Zopf. Die Pilze, 1S90 ; and Beitrage z. Physiol, u. morphol. niederer Organismen, 

Heft iii., 1893. 

3 Dangeard. “ Recherches sur la reprod. sexuell d. champignons” Le 
Botaniste, 1893. Pairault and Raciborski. “Sur les noyaux des Uredinees” 
Jour, de Botanique, 1895. 

4 Raciborski. Flora (ergcinzungsband), 1895, p. 439. Compare also : Stras- 
burger. “ UeberperiodiseheReduktion d. Chromosomenzahl im Entwickelungsgang 
d. Organismen,'’ Biol. Centralblatt, 1894, p. 862. Wager. “ Nuclear division in 
the Hyinenomycetes,” Annals of Botany, 1893, p. 490. 


13G 


ASCOMYCETES. 


Uredineae, we designate amongst the Aseomycetes, as asci, and 
amongst the Protomycetes and Basidiomycetes as basidia. This cell, 
a huinologue of the primary embryo-cell of the Archegoniatae 
and Embryonatae, indicates a turning-point in the development, 
the beginning of a new generation. It either becomes a resting- 
spore, as in Phycornycetes, Ustilagineae, Uredineae (exclusive of 
Coleosporium and Chrysomyxa), or divides at once to form free 
endospores as in the Aseomycetes, and exospores in the Protomycetes 
and Basidiomycetes. From these facts the distinction between 
basidiospores and conidia, asci and sporangia, teleutospores and 
chlamydospores, has been for the first time distinctly proved.” 

ASCOMYCETES. 

The Aseomycetes show relationship to the higher fungi in the 
possession of a septate mycelium. Their spores are produced in 
cylindrical sacs called asci, whence the name Aseomycetes is 
given to the group. 

The primary nucleus of each ascus results from the copulation 
of two nuclei of distinct origin and with no relationship to each 
other. From the division of this nucleus and its daughter- 
nuclei, there are produced a number of free endospores varying 
according to the species. These may remain unicellular or, by 
means of septa, become many-celled bodies from each of whose 
individual cells germ-tubes may develop. It is advisable to give 
the name spore to each cell-group which develops from one 
nucleus . 1 

Ascospores are never zoospores, but are always quiescent and 
possess a cell-membrane. They are generally forcibly expelled 
from the asci. The asci originate either directly from the my- 
celium, as in the Saccharomycetes and some Kxoasceae , 2 or a part 
of the mycelium becomes differentiated into an ascogenous layer. 
The ascogenous layer may include only a few cells, as in the 
lower forms, or it may be a complex tissue. In the higher forms 
the aggregations of asci are enclosed in coverings, but the asco- 
genous layer takes no part in the formation of the enclosures 
nor of the accessory organs known as paraphyses and periphyses. 

1 De Bary held that each individual cell capable of germination is a spore, the 
single multi-cellular spores he designated sporidesmia. 

-Hansen, Centralbl. f. liaelenoloipe und ParaMUnhinde, 1 893. 

Sadebeck, Die parasitischm Exoascetn, 1893. 


ASCOMYCETES. 


137 


This ascogenous layer has been named the ascogonium, and it 
was at one time generally believed that it arose from a female 
cell, the homologue of the oospore of lower fungi ; a hypha 
which applied itself to the ascogonium was regarded as a male 
or antheridial organ, and called a pollinodium. In other cases, 
a thread-like hypha, which proceeded from the ascogonium, was 
called a trichogyne ; it was believed to be fertilized by means 
of certain very small cells (spermatia) produced in special 
structures, the spermogonia. These spermatia, though known 
for a long time, have only recently been made to germinate, and 
that only in nutritive solutions. The significance of the pol- 
linodium as a male organ is not necessarily wrong, though it 
may be a functionless structure, such as we already know 
antheridia of many of the Phycomycetes to be. So also we may 
still consider the spermatia as sexual bodies, even though they 
germinate like spores, for their never-failing production before 
aecidia would seem to suggest some relationship. In the 
following pages we will speak of these little spores, sometimes as 
spermatia, sometimes as conidia. 

reproduction of Ascomycetes may also take place by conidia 
and chlamydospores, capable of germination to form mycelia. 

Amongst the Ascomycetes one finds the higher stages of de- 
velopment accompanied by an almost complete enclosure of the 
aggregations of asci. The asci of the Saccharomycetes originate at 
any spot whatever between the mycelial threads ; in Gymnoascus 
one finds a loose web of mycelium forming a covering to the asci ; 
in higher forms an enclosure (sporocarp) of definite shape is 
developed. On this account, the forms which do not produce 
sporocarps are classed together as Gymnoasci, the sporocarpous 
forms as Carpoasci. Amongst the latter, the sporocarp of the 
higher forms possesses a definite opening from which the spores are 
emitted after liberation from the asci ; certain lower forms (Peri- 
sporiaceae) have indeed sporocarps, but these possess no opening, 
and it is only after they have ruptured or decayed that the 
spores are set free. 

A . Gymnoasci. 

(Ascomycetes without Sporocarps.) 

The asci are produced over the whole mycelium, or from a 
special ascogenous part of it, and are never enclosed in a sporo- 
carp. 


138 


ASCOMYCETES. 


The genera placed in the Gymnoasei are : Dipodascus, Ere- 
mascus, Ascoidea, Protomyces, Taphrina, Exoascus, Magnusiella , 
Saccharomyces, Monospora, Endomyces, Podocapsa, Eremothecium, 
Oleina, Bargellinia, Ascodesmus, Gymnoascus, Ctenomyces. 

Protomyces, Taphrina, Exoascus, Magnusiella, are true parasites 
of higher plants: Endomyces, Ascoidea, and Saccharomyces occur in 
the flux diseases of trees ; the others are saprophytes, or 
parasites on fungi ( Podocapsa ). 

Protomyces . 1 

The genus Protomyces possesses a septate mycelium, and 
in this shows relationship with the higher fungi. It is also 
distinguished by the formation of sporangia (asci), which are 
produced in an intercalary manner like the chlamydospores of 
the Ustilagineae. Conidia are also developed, which sprout 
yeast-like and conjugate like those of many Ustilagineae. 
Thus Protomyces stands in one direction between the sporangi- 
ferous lower fungi and the Ascomycetes, and in another between 
the Ascomycetes and the non-sporangiferous Ustilagineae. 
Prefeld allocates them with the Ascoidea and Theleboleae to 
his intermediate group the Iiemiasci. I)e ltary ( Comparative 
Morphology of the Fungi) agrees with Fisch in placing them 
between the Chytridiaceae and Ustilagineae, but in his “Bcitragcn ” 
considers them as the simplest forms of Ascomycetes. 

In any case they do not show very close relationship with 
any group. 

Protomyces macrosporus, Ung. (Britain). This parasite lives 
by means of an intercellular septate mycelium in leaves and stems 
of Umbelliferae, especially Aegopodium Podagraria, Chacrophyllum 
hirsutum, Hcraclcum Sphondylium, etc. It also causes injury to 
cultivated carrots. 

The disease shows itself externally as pustule-like swellings 
on the organs attacked. These are caused, as shown in the 
figures, by a mycelium which pierces the epidermis, and, after 

■Do Haiy, Untermichnuiji n id>. <1. Brandpilse it. </. durch tie rcnirsarhhn 
Kraiikhfiliti d. Ptta men. Herlin, ISM. 

l)o Bary u. Woronin, Beitriii/e z. Morph, it. Physiol, d. Pihr, I. 15>l., 1SG4. 

Fiscli. H< itriojt z. Kf initnun d. Chytridiacem , 1S84, j>. 41. 

Brefeld, Hefepilze, p. 17(5. 

B. Meyer, “ Untersuchungen ul >. die Entwickelung einig. porasit. Pil/.e bei 
saprophyt. Ernfilirung.” Inaugural Dissertation, 1SSS. 


PROTOMYCES. 


139 


distributing itself through the intercellular spaces, stimulates the 
parenchyma-cells of the host to growth and cell-division. The 



Fig. 45 .—Protomyces ma crosporv.s on leaf-stalk of Aegopodiv.m Podagraria. 
A, Mycelium and sporangium in the tissue under the epidermis. B , Sporangia 
in stages of development, (v. Tubeuf del.) 



latter is a secondary process and consists (see Tig. 9) in the 
formation of exceedingly delicate membranes inside the original 



Fig. 46. Protomyces macro spor us. Section of petiole of A eyopodium with two 
swellings containing spores. Secondary cell-walls have been formed, and a 
collencliyma region lies between the two swellings, (v. Tubeuf del.) 


cells of the parenchyma, so that they become divided into 
younger cells rich in protoplasm and each showing a distinct 


140 


ASCOMYCETES. 


cell-nucleus. This tissue so formed may be compared to the 
nutritive tissue formed secondarily from parenchyma as a result 
of other fungoid diseases, e.g. in violas attacked by Urocystis 
violae. If the formation of sporangia ensues in parts which 
would normally become collenchvma, the tissues there remain 
thin-walled. 

The sporangia of Protomyces, according to I)e Bary, 1 begin to 
develop as soon as the young leaves and shoots of the host- 
plants emerge above the ground in spring. The sporangia first 



Fig. 47 . — Protomyces macrotporm. Section through swollen leaf -stalk of Acpo- 
podium. Towards the light end the cells are normal, elsewhere they arc, under 
the influence of the mycelium, much enlarged and secondarily divided ; two 
roundish sporangia lie in this tissue, (v. Tubeuf del.) 


appear as series of swellings on the hyphae and are easily 
detected in deformed plants as large thick-walled bodies lying 
in the intercellular spaces. They are liberated on decay of the 
host-plant, and in spring the contents swell up so as to rupture 
the thick outer wall, and the endosporium emerges as a vesicle 
or sporangium into which the protoplasmic contents pass to 
form numerous rod-shaped spores. The spores are ultimately 
expelled with considerable force, and, after conjugating in couples, 
they send forth a germ-tube which penetrates again into the 
tissues of the host-plant. 


De Bnry, Beitrdge z. Morph, u. Physiol. <1. Pilzc, albo Bo! an. Z titling, 1S74. 


PROTOM YCES. 


141 


In nutritive solutions germination does not take place in this 
way, but is replaced by a yeast-like sprouting of the sporangial 
spores without disjunction of the sprout-cells . 1 

According to Meyer, these sprout-cells produce elongated 
hypha-like cells with which, however, he did not succeed in 
infecting a new host-plant. He also found that spore-conjuga- 
tion takes place better in water than in nutritive solutions. 

Pr. fuscus. Pk., occurs on Anemone in America. 

Pr. pachydermus, Thiim., occurs on Compositae esp. Taraxacum. 

Pr. radicicolus, Zopf . 2 A form similar to P. macrosporus, 
but furnished with coiled haustoria. It lives intercellular in roots 
and kills the cells, without, however, causing external hypertrophy. 
Zopf found it in roots of Stiftici Chrysantha and Achillea 
clypcolata in the botanic garden of Halle, but the plants were 
not killed, because their roots were not all attacked . 3 


Endomyces. 

The asci contain four spores which do not produce conidia. 
The sterile hyphae give rise to chlamydospores and an oidial 
form of spore. 

Endomyces decipiens lives as a parasite on sporophores of 
Ayaricus melleus. 

According to Ludwig, species of Endomyces have much 
to do with the slime-flux of trees, which contain in addi- 
tion other forms of Gynmoasci, e.g. Saccharomyces Ludwigii, 
Ascoidca rubescens, etc. We shall here devote some space to 
the general consideration of the slime-flux of living stems. 
This phenomenon remained uninvestigated until Ludwig took it 
up and directed attention to it. He found several species of 
considerable systematic interest, the pathological effects of which, 
however, require further investigation. 

1 Brefeld, Scliimmelpilze, Heft ix., 1891. 

- Zopf, Zur Kenntniss d. Infectionskrankh. niederer Thieve u. Pjianzen, 18S8. 

3 Saccardo, who ranks the Protomycetes along with the Chytridiaeeae, includes 
a large number of species. Magnus places Protomyces (?) Jilicinus, Niessl. ( Vtr- 
hund. des internat. botan. Konyress in Genoa, 1892) in the neighbourhood of 
the Phycomycetes ; it, however, possesses a septate mycelium and stylospores 
which are enclosed in a coat so that they recall spores of the Uredineae, hence 
Magnus named it Uredinopsis filicina on Phtyopleris vidyaris. This species 
must not be confused with the species of Uredo occurring on Pheyopteris, 
D ryopteris, Cystopteris frinjilis, and Scolopendrium officinale. 


142 


ASCOMY CETES. 


The Slime- or Mucilage-flux of Trees. 

This is a very common phenomenon in our avenues, parks, 
and forests. It can be observed during the period of vegetation 
on several species of trees, particularly on spots wounded by 
removal of branches, by frost rupture, or by some other cause. 
The wound may, however, be so grown over or occluded that 
at first sight the slime appears to flow from the uninjured 
bark. These slime-fluxes are very common on dead branch- 
snags and in places affected with sun-stroke or frost- wounds ; 
while I have frequently found them on dead tree-stools 
and on wooden water-pipes where the water trickled from 
some fissure. It is thus probable that they are always 
produced on the site of some wound, although Ludwig, 
without giving any details, says that there may be no previous 
injury. I have never observed any case where a tree with a 
slime-outflow became sickly and died, and the cases of death 
recorded by Ludwig are probably due to some other cause. 
Ludwig, however, says decidedly that the white slime-flux on oak, 
as well as the brown flux of apple, horse-chestnut, and 
others, are really parasitic phenomena. I must say, however, 
that I have carefully examined the occluding tissues on frost- 
cracks showing slime-flux, and found them quite healthy. 

The white slime-flux of the oak. 1 

According to Ludwig, the white slime-flux of the oak and 
other species of trees takes place during moist weather, and 
from June to September. It flows from branch-scars, former 
frost-ruptures, and other wounded places ; also from apparently 
uninjured bark. Ludwig believes that such wounds are infected 
by the agency of insects, particularly hornets ; that the disease 
spreads through the bark and breaks out in various places. On 
such spots the edges of the wound are alternately occluded 
and killed again, so that a flux-wound may come in course of 
time to resemble a “canker-spot.” Large areas of the bark die off, 
and the death of the wood frequently follows. 

1 Ludwig : (1) “ L T ebcr Alkoholgidining u. SchleiniHuas lebeuder Biiume u. deren 
Urheber.” Be >'■ <!■ (h ntucli boron. (Its. , 1 SSti. (2) “ Uebor profuse (luimnose d. 
Eichen u. weiter. Mitth. Ub. Alkoholgahrung u. Sehleimlluss lebender lliuinie.” 
Centrbl.f. Iiakt. u. Parasite idunde, 1890. (3) Lthrbnch , 1892. (4) Forst.-natur- 
wU8. Zeitachr., August, 1894. 


ENDOMYCES. 


143 


The slime-flux is the product of an alcoholic fermentation and 
has at first a distinct odour of beer. The fermentation produces 
a transparent foam in which are found Endomyces Magnusii 
(Ludw.) and a yeast, Saccharomyces Ludwigii (Hansen); this latter, 
Ludwig regards as a stage of the Endomyces. Later a gelatinous 
slime is developed in the foam from the presence of Lcuconostoc 
Lagerheimii (Ludw.) Since this latter plant does not appear 
in the early stages of the disease, it cannot be the cause, and 
Ludwig says that the alcoholic fermentation due to the Endomyces 
always appears first ; this conclusion requires confirmation. 

The milky outflow of trees . 1 

Towards the end of winter and in spring a white foamy slime 
flows from freshly cut birches or hornbeams. According to 
Ludwig, this is due to Endomyces vernalis (Ludw.) 

Red slime-flux . 1 

Ludwig found on the cut twigs of hornbeam, a red fungus 
which he called Bhodomyces dendroporthes. This may occur alone 
or along with the white flux, which it colours red. 

Brown slime-flux . 3 

This is found on apple-trees, elms, birch, horse-chestnut, 
poplar, oak, etc., from spring till winter. The slime, Ludwig 
says, is developed in the wood, and breaks through, causing 
the bark to decay. The wood is destroyed and smells of butyric 
acid. The slime contains micrococci ( Micrococcus dendroporthes, 
Ludw.) and a form of Torula (T. monilioidcs). 

In Thuringia, many avenue-trees ( e.g . chestnuts, apples, and 
birch), are reported to have been killed from this cause. That 
the disease was really the result of a Bacterium, and that death 
was due to this slime-flux, has yet to be proved, as Ludwig 
himself states. 

Black slime-flux. 

Ludwig considers briefly some forms he found in a black 
slime-flux observed by him on beeches. 

1 Ludwig, Lehrbuch der nied. Kryptogamen, 1S92. 

2 Ludwig, Centralbl. f. Baht. u. Parasitenkunde, 1SS8. 


144 


ASCOM Y CETES. 


Chocolate-brown slime-flux. 1 

A slime-flux of this colour appears on the stumps, of felled 
beeches ; it contains numerous forms of Oiclium, and later Ascobolus 
Constantini (Roll) is developed in large quantity . 2 


THE PARASITIC EXOASCEAE . 3 

In this family are included the genera Exoascvs, Magnusiella, 
and Taplirina. The asci of most of the known species are 
produced from a mycelium which lives under the cuticle of the 
host-leaf, in a few (e.y. Magnusiellct Jlava), the mycelial 
hyphae are developed between the cells of the epidermis, 
while in others ( e.y . M. potentillae), the mycelium permeates 
the whole leaf-tissue and the asci arise from hyphae situated 
under the epidermis. T. Laurcncia and a few others have an 
intracellular mycelium, and produce asci inside the epidermal 
cells. A number of species are known to possess a perennating 
mycelium, in the remainder the hyphae are wholly used up in 
the formation of asci. 

The ascospores produce conidia before leaving the asci, which 
are therefore frequently found filled with minute conidia instead 
of the usual ascospores. In nutritive solutions the conidia sprout 
yeast-like ; on a host-plant, they give rise to a hypha which 
penetrates the cuticle. 

1 Ludwig, “Ein neuer Pilzfluss d. Waldbaume,” Foret. -naluririss. ZeitschriJ ?, 
1893, and 1894. 

2 Kruger has found various micro-organisms, including a fungus (Protothcca) 
and several algae, in the sliine-tlux of broad-leaved trees. (Zopf, Beitr. s. 
Physiol, v. Morph, nied. Organismen, 1894.) 

3 Sadebeck : (1) Untersuch. iih. die Pilzgaltung Ejoosciis, 1884. (2) Kritisehc 

Untersuch. iib. die durcli Taphrina-A rteu herrorgebraehten Baumlrankheiten, 
1890. (3) Die parusitischen Exoasceen, 1893. (4) “ Kinige neue Beobachtungen u. 

kritische Bemerkungen Ub. die. Exoasceae,” Bcr. d. aeutsch. hot an. ties., 1893. 

Johanson : (1) Studier offer Sramnsldget Taphrina, 1887. (2) Out Scamp- 

sldgtet Taphrina orh dithUrande Srenska arter, 1883. 

Rostrup, Taphrinaceae Daniae, 1890. 

I)e Bary, Beitrage s. Morph, it. Physiol, d. I'ilze, 1804-1S70. 

(liesenhagen, “ Die Eutwickelungsreihen der parasitischen Exoasceen.'' Flora, 
Erydnzuiigsbaiul, 1893. With numerous figures from microscopic sections. 

Atkinson, “ Leaf-curl and plum-pockets.” A contribution to the knowledge of 
the prunicolous Exoasceae of the United States. Cornell Unit'. Ayric. Exp. 
Station, Bulletin 73, 1S94. With numerous illustrations. 

Patterson, “A study of N. America parasitic Exoasceae.” Bulletin of the 
Lah. vat. hist.. Unit', of Iotra, 1893. 

Smith, “ Untersuch. der Morph, u Anatomic der durch Exoasceen verursachten 
Dcformationen.” Forst.-na/iirwiss. Zeitschrijl , Munich, 1S94 ; Italian, translation 
by Bcrlese, Pi fist a di Patologia, 1893. 


THE PARASITIC KXOASCEAE. 


145 


The presence of a perennating mycelium is the cause of 
many so-called “ witches’ brooms ” on woody plants. In fact, 
the majority of the structures known by that name are caused 
by species of Exoascvs, though these of barberry, silver hr, 
acacia, and buckthorn, are due to Uredineae, and others are 
ascribed to mites (Ph;jto]>tus). 

“Witches’ Brooms” (Hexenbesen) are bushy growths, which 
remind one at first sight of stranger-plants growing, like 
mistletoe, on the branches of other plants. They .generally 
originate from a bud which has been infected during the previous 
summer, either directly or through its subtending leaf. This bud 
produces a twig capable of abnormally increased growth, most of 
its sleeping buds are developed into branches, and the whole 
system shows marked negative geotropism. (See Fig. 3). The 
spores of the fungus are produced on the leaves of the broom. 

The characteristic features of a witches’ broom are : that, 
without regard to the direction of the branch on which it is 
borne, it is negatively geotropic in a marked degree, and 
endeavours to develop like a terminal leader shoot ; that the 
point of infection is distinctly conspicuous as the starting point 
of the broom. Sadebeck regards any twig-hypertrophy as a 
witches’ broom, even that of Exoascus Tosquinetii where there 
is no basal swelling and the twigs exhibit oidy very slight 
negative geotropism. 

The forms of witches’ brooms are very varied. Amongst 
the best known are the hanging broom-like masses developed 
from buds of the leader shoots ( e.g . on cherry trees). As a 
result of the rich growth of twigs and their premature death, 
many of these brooms become tangled nest-like structures. The 
twigs in some are much elongated, in others shortened, in 
every case, however, they are abnormally numerous. As a rule 
the original leader shoot, on which some lateral bud has developed 
into a witches’ broom, shrivels up and dies, its contents being, 
as it were, absorbed by the hypertrophied branches. Other 
general features have already been discussed in Part I. of 
this book. 

Smith 1 found that the form of the witches’ broom is not 
determined exclusively by the fungus. The perennating my- 
celium indeed gives the first impetus towards its formation, 

1 Smith, loc. cit. 

K 


116 


ASCOMYCETES. 


but it is completed by the weight of the broom itself, the 
excessive development of sleeping buds, and the premature 
death of twigs. Smith also investigated the anatomical changes 
occuring in witches’ brooms due to Emasceae. From his 
resum.4 we select the following : “ In a witches’ broom the 
increased thickness of the twigs and branches is due to a 
proportionally greater increase, in the bark than in the wood, 
the hypoderm, especially, having its cells more numerous and 
larger, while their normal arrangement in longitudinal rows 
is lost. The cork-cells are enlarged and retain their plasma- 
content longer. The phelloderm is better developed. In the 
sclerenchyma-ring, the primary bundles of bast-fibres are smaller 
and further apart from each other, or they may be quite 
absent ; the bast-fibres are shorter and have thinner walls ; 
sclerenchymatous cells are more numerous, larger, and have 
thinner walls. The phloem is increased chiefly through enlarge- 
ment and increase in number of its medullary rays; phloem 
crystal-deposits tend to be multiplied. In the wood, the parts 
most enlarged are the pith and medullary rays ; tracheae are 
more numerous, but their component elements are shorter ; the 
wood-fibres have thinner walls, wider lumina, and are often 
chambered ; the normal course of the long elements is much 
disturbed by the greatly enlarged medullary rays. 

Sadebeck has recently divided the parasitic Eroasccai into 
these genera : (a) Maynusidla, with asci isolated on the ends 
of mycelial threads which lie between the epidermal cells ; in 
the other genera the asci arise from a subcuticular hymenium ; 
{h) Taplirina, without a perennating mycelium ; (c) Exoascvs, 
with a perennating mycelium ; (//) Taphrinopsis may be taken 
as another genus. Ascomycrs he does not reckon with the 
Ewajceae. 

Brefeld divides the family into E.roa.icux, with eight spores in the asms, 
and Taphrina, with four-spored asci. Sadebeck shows, however, that 
eight is the normal number of spores in all the species, and that variation 
therefrom is frequent, four or more spores or numerous eonidia being 
formed. 

Schroeter separates the genus Ma</nusirlla, as Sadebeck has done, then 
divides the remainder into E.voatcns with eight-spored asci at time of 
maturity, while those with many-spored asci are placed under Taphria 
(the older name given to Taphrina) 


THE PARASITIC EXOASCEAE. 


147 


According to Sadebeck, the Exoasceae may be divided as 

follows : 


Exoascus. 


The mycelium perennates in the tissues of twig or bud. The 
subcuticular mycelium is developed from the perennating one, and 
becomes completely divided up, without any differentiation, into 
ascogenous pieces. The species are all parasites and produce 
hypertrophy of leaves, dowers, and shoots. 

A. The mycelium perennates in the inner tissues of the 
shoot. Thence, in the next vegetative period, it sends branches 
into the leaves in process of development, at first into the 
inner tissues, but later subcuticular for the formation of re- 
productive parts of the fungus. 

(1) Asci developed in the carpels, which in consequence 
become hypertrophied ; asci with a stalk-cell : E. pruni 
Fuck. E. liostrupianus Sad. E. communis Sad. E. 
Farlowii Sad. E. rliizipes Atk. * E. longipes Atk. E. 
confusus Atk. E. cecidomophilus Atk. 

(2) Asci developed only in the foliage leaves. 

(a) Asci with stalk-cell : E. insititiae Sad. E. cerasi 
(Fuck.). E. nanus (Joh.). E. deformans (Berk.) E. 
decipiens Atk. E. acerinus Eliass. 

( b ) Asci without stalk-cell : E. purpurascens (Ell. and 
Ever.). E. aesculi (Ell. and Ever.). 

(3) Asci developed on leaves and fruits. 

(a) Asci with stalk-cell : E. mirabilis Atk. 

B. The mycelium perennates in the buds of host-plants 
and issues thence in the next vegetative period to develop in 
young leaves, subcuticular only. 

(1) Asci only on the foliage leaves. 

(«) Asci with a stalk-cell : E. crataegi (Fuck.). E. minor 
Sad. E. Tosquinetii (West.) E. cpipliyllus Sad. E. 
turgidus Sad. E. betulinus (Bostr.). E. alpinus (Joh.). 

(b) Asci without a stalk-cell : E. carpini Rostr. E. bactcri- 
ospermus (Joh.). E. Kruchii Vuill. 

(2) Asci on carpels ; without stalk-cell : E. alni incanae 
Kuhn. E. Johansonii Sad. E. rhizophorus (Joh.). 

(3) Mycelium grows intercellularly. E. cornu ccrvi Giesh. 


148 


ASCOMYCETES. 


Taphrina. 

The whole mycelium is subcuticular and differentiated into 
one portion, which remains sterile, and into an ascogenous part. 

Perennation of the mycelium does not occur. The species pro- 

duce spots or hypertrophy on leaves or carpels. 

a. The fertile hyphae are completely used up in the for- 
mation of the asci. 

(1) Asci with a stalk-cell: T. bullata (Berk, and Br.). 

T. ostryae Mass. T. Sadebeckii Joh. T. aurea 

(Pers.) (may also occur without a stalk-cell). 

(2) Asci without a stalk-cell : T. filicina Rostr. T. 

polyspora (Sorok.). T. carnea .Joh. T. coerulescens 

(Mont, and Desm.). T. virginica Seym, and Sad. 

T. extensa (Peck.). 

B. The fertile hyphae are not completely used up ; asci with 
a stalk-cell : T. betulae (Fuck.). T. vlmi (Fuck.). T. celtis Sad. 

Taphrinopsis. 

Mycelium and hymenium developed only inside the epidermal 
cells. T. Laurencia Giesh. 

Magnusiella. 

The mycelium inhabits the inner tissues of living plants and 
is always parasitic. Asci are formed at the extremities of 
branches of the mycelium, either between the epidermal cells 
or between cells of the inner tissues. The asci contain more 
than four spores, which generally produce conidia inside the 
ascus. The species generally cause leaf-spots, more rarely they 
appear on stems. 

(a) Asci without a stalk-cell : .1/. potcntillae (Fail.). M. lut- 
csccns (Rostr.). M. f lava (Fail.). M. gitliaginis (Rostr.). M. 
umbel lifer arum (Rostr. ). 

(b) Asci with a stalk-cell : M. fasciculata Lag. et Sad. 

Giesenhagen ( loc . cit.) conies to the conclusion that the species 
of the parasitic Exoasceae have developed from a common 
ancestor simultaneously with the species of the higher plants 
inhabited by them, and that the development of host and parasite 


THE PARASITIC EXOASCEAE. 


H& 

has progressed side by side. He shows that Exoasceae, living 
on related hosts, agree so closely in their ascogenous forms,, 
that it is evident they are generically related species. On this 
ground he sets up a genus containing many species, and names 
it Taphrina. According to the host-plants, this genus is 
divided into four stems, and from it twenty-five species are 
separated off as the genus Magnusiella. Giesenhagen’s systematic 
division, gives a synopsis of the host-plants and their distri- 
bution as follows : 

I. Genus. Taphrina : asci club-shaped to cylindrical. 

A. Filices- stem, on Ferns : asci slender, club-shaped; tapering to 
both ends, rounded apex, greatest breadth in the upper quarter 
of the ascus. 

T. cornu cervi (Giesh.) on Aspidium aristatum in East 
Indies and Polynesia. 

T. filicina (Rostr.) on Aspidium sjnmdosum in Scan- 
dinavia and Balkan-peninsula. 

T. Laurencia (Giesh.) on Pteris quadriaurita in Ceylon. 

T. fasciculata (Lag. et Sad.) on Ncplirodium in South 
America. 

T. lutcscens (Rostr.) on Aspidium Thclyptcris in Denmark. 

B. Bctula- stem on Julifiorae : asci plump, cylindrical, with 
rounded apex or even a slight depression there. 

(1) On U Imaceae : T. ulmi (Johan.) on Ulmus montana and 

U. campestris in Central Europe and North America. 

T. celtis (Sad.) on Celt is australis in North Italy and 
Switzerland. 

(2) On Betulaceae. 

(a) On Bctula : 

T. alpina (Johan.) on B. nana in Scandinavia. 

T. nana (Johan.) on B. nana in Scandinavia. 

T. betulae (Johan.) on B. verrucosa, B. pubescens, and B. 
turkestanica in Central Europe. 

T. betulina (Rostr.) on B. pubescens, and B. odorata in 
Germany, Denmark, and Scandinavia. 

T. carnea (Johan.) on B. odorata, B. pubescens, B. nana, 
B. intermedia in Scandinavia, Tyrol, and Silesia. 

T. bactcriospermum, (Johan.) on B. nana in Scandinavia 
and Greenland. 


150 


ASCOMYCETES. 


T. flava (Farl.) on B. populifera and B. papyracea in 
North America. 

T. turgida (Sad.) on B. verrucosa in Germany and Tyrol. 

(b) On Alnus: 

T. epiphylla (Sad.) on A. incana in Europe. 

T. Sadcbeckii (Johan.) on A. glutinosa in Europe. 

T. Robinsoniana (Giesh.) on A. incana in U.S. America. 

T. Tosquinetii (Magn.) on A. glutinosa in Europe. 

T. alni incanae (Magn.) on A. incana in Europe. 

(T. alni glutinosae (Tubeuf) on A. glutinosa in Italy, 
Sweden, and Denmark.) 

(c) On Cupuliferae: 

T. ostryac (Mass.) on Ostrya carpinifolia in Tyrol and 
Italy. 

T. virginica (Sey. et Sad.) on Ostrya rirginica in North 
America. 

T. carpini (Rostr.) on Carpinus Betulus in Europe. 

T. australis (Atk.) on Carpinus americana in North 
America. 

T. Kruchii (Vuill.) on Quercus lie ./■ in Italy and France. 

T. coerulescens (Tul.) on Quercus sessiliflora, Q. pedun- 
culata, Q. pubcsccns, Q. alba, etc., in Europe and 
America. 

(d) On Salicaceae : 

T. aurea (Fries.) on Populus nigra, B. pyramidalis and 
P. monilifera in Europe and North America. 

T. Johansonii (Sad.) on Populus tremu/a, P. trcmuloidcs, 
and P. grandidentata in Europe and North America. 

T. rhizophora (Johan.) on Populus alba in Europe. 

<;. Prunus-stem on Rosaceae : asci slender and club shaped. 

(a) On Pomaccac : 

T. crataegi (Sad.) on Crataegus Oxycantlm in Europe. 

T. bullata (Tul.) on Pyrus communis and Cydonia japoniea 
in Europe. 

(b) On Pruneae : 

T. deformans (Tul.) on Pcrsica vulgaris ami Amygdatus 
communis in Europe and North America. 

T. minor (Sad.) on Primus CJiamareerasus near Hamburg 
and Munich. 


THE PARASITIC EXOASCEAE. 


151 


T. insititiae (Johan.) on Primus Insititia and P. clomestica, 
in Europe, and P. pennsylvanica in North America. 
T. decipiens (Atk.) on Prunus americana in North 
America. 

T. cerasi (Sad.) on Primus Cerasus and P. Chamaecerasus, 
in Europe, and P. avium, in North America 
T. pruni (Tul.) on Primus domestica and P. Padus in 

Europe and North America. 

T. mirabilis (Atk.) on Primus angustifolia, P. liortulana 
and P. americana in North America. 

T. Farlowii (Sad.) on Primus serotina in North America. 
T. confusa (Atk.) on Primus virginiana in North 
America. 

T Rostrupiana (Sad.) on Primus spinosa in Europe. 

T. communis (Sad.) on Primus maritima, P. pumila, P. 

americana and P. nigra in North America. 

T. longipes (Atk.) on Primus americana in North America. 
T. rhizipes (Atk.) on Prunus triflora in North America. 

(c) On Potenlilleae : 

T. potentillae (Johan.) on P. sylvestris, P. canadensis, and 
P. gcoides in Europe and North America. 

D. Aescidus- stem on Eucyclieae : asci plump, cylindrical, with 
hat or rounded apex. 

(a) On Sapindaceae : 

T. aescidi (Ell. et Ever.) on Aesculus californica in 

California. 

(b) On Anacardiaceae : 

T. purpurasccns (Robins.) on Rhus copallina in North 
America. 

(c) On Acerineae : 

T. accricola (Mass.) on A. campestrc and A. Pseudoplatanus 

in Italy. 

T. acerina (Eliass.) on A. platanoides in Sweden. 

T. polyspora (Johan.) on A. tartaricum in Europe. 

II. Genus. Magnusiella : asci ovoid or spheroidal. 

M. githaginis (Sad.) on Agrostemma Githago in Denmark. 
M. umbelliferarum (Sad.) on Hcracleum Sphondylium, 
Peucedanum palustre, and P. Oreoselinum in Europe. 


152 


ASCOMYCETES. 


The Ewasceae may be grouped, according to the symptoms 
of the disease produced, as follows ; for this purpose we shall 
class all the species as one genus, ‘ Exoascus’ (or Taphrina ): 

I. Species which cause deformation of the ovary or other part 
of the fruit. 

E. pruni (Fuck.) on Prvnus domestica, 1\ Padus, P. vir- 
giniana. 

E. Rostrupianus (Sad.) on Prvnus spinosa. 

E. communis (Sad.) on Prunus pumilla, P. maritima, P. 
nigra, P. americana. 

E. Farlovni (Sad.) ( E . varius, Atk.) on Prunus scrotina, 
causing also deformation of twigs. 

E. longipes (Atk.) on Prunus americana. 

E. confusus (Atk.) on Prunus virginiana. 

E. rhizipes (Atk.) on Prunus triflora. 

E. cecidornophilus (Atk.) on insect-galls on the fruits of 
Prvnus virginiana. 

E. mirabilis (Atk.) on Prunus angvstifo/ia, hortu/ana, 
P. americana. 

[Also species on Pi'unus subcordata, P. Chicasa, and /’. 
pennsyl va nica.] 

E. alni incanae (Kuhn) (E. amcntorum. Sad.) on Ain us 
incana. 

E. alni glutinosae (Tubeuf) on Alnus g/ufinnsa. 

E. Robinsonian us (Giesh.) on Alnus incana . 

E. Johansonii (Sad.) on Popufus trnnula, P. tremuloidcs, /’. 
grandidentata. 

E. rhizoplwrus (Johan.) on Populus alba. 

II. Species which (1) produce witches’ brooms, or (2) at least 
cause deformation of shoots ; asci produced on the leaves. 

(1) E. epiphgllus (Sad.) (E. borealis, Johan.) on Alnus 
incana (uniform grey coating of asci on both sides 
of leaf.) 

E. turgidus (Sad.) on Bctula verrucosa (coating of asci on 
under surface accompanied by slight crumpling of 
leaf). 

E. bdufinus (Rostr.) on Bctula pubcsccns and B. odorata 
(coating of asci on under surface). 


THE TARASITIC EXOASCEAE. 


153 


E. alpinus (Johan.) on Beheld nana (coating on under 
surface). 

E. carpini (Rostr.) on Carpinus Betulus (coating on under 
side, and crumpling of leaf). 

E. cerasi (Fuck.) on Prunus Cerasus and B. avium (coating, 
chiefly on under side, and crumpling of leaf). 

E. insititiae (Sad.) on Prunus Insititia, P. domestiea, P. 
pennsylvanica, (P. spinosa ?) ; (coating on under side, 
and crumpling of leaf). 

E. acerinus (Eliass. 1 ) on Acer platanoides ; (asci on both 
surfaces). 

E. aesculi (Ell. et Ever.) on Aesculus calif ornica ; (coating on 
both sides). 

E. Krucliii (Vuill.) on Quercus Ilex. 

E. cornu cervi (Cfiesh.) on Aspidium aristatum. 

E. Laurencia (Giesh.) on Pteris quadriaurita (with deforma- 
tion of leaves). 

(2) E. nanus (Johan.) on Bctula nana (white coating on 
upper side). 

E. baderiospermus (Johan.) on Bctula nana (coating on both 
sides). 

E. decipiens (Atk.) on Prunus americana (coating on both 
sides). 

E. purpurascens (Ell. et Ever.) on Rhus copallina (crum- 
pling and red-colouration). 

E. Tosquinetii (West.) on Alnus glutinosa and A. glut, x 
incana (large blisters and elongation of shoots). 

E. pruni (Fuck.) on Prunus domestiea (blistering and crum- 
pling). 

E. minor (Sad.) on Prunus Chamciecerasus. 

E. deformans Berk, on Persica vulgaris and Amygdalus 
communis (blistering and crumpling). 

E. cratacgi (Fuck.) on Crataegus Oxyacantha (spots and 
blisters on the leaves). 

E. mirabilis (Atk.) on Prunus angustifolia, P. hortulana, 
P. americana (on twigs, leaves, and fruits). 

E. celtis (Sad.) on Celtis australis (brown spots). 

E. githaginis (Rostr.) on Agrostemma Githago. 

1 SvensJca Vet.-Akad. Hand!. 20, 1895. 


1 54 


ASCOMYCETES. 


III. Species which produce (1) pustule-like outgrowths, (2) 
leaf-spot, or (3) smooth coatings of asci. 

E. aureus (Pers.) on Populus nigra (incl. pyramidalis) 
and P. monilifera. 

E. polysporus (Sor.) on Acer tartaricum and A. Pseudo- 
platanus. 

E. bullatus (Berk, et Br.) on Pyrus communis and Cydonia 
japonica. 

E. carncus (Johan.) on Betida nana, B. odorata, and B. 
intermedia. 

E. coeridescens (Desm. et Mont.) on Quercus piibcscens, Q. 
sessiliflora, Q. Perris, Q. laurifolia, Q. rubra, Q. tinctoria, 
Q. aquatica. 

E. Sadebeckii (Johan.) on Alnus glutinosa. 

E. vhni (Fuck.) on Ulmus campestris, U. montana, and U. 
americana (spots and blisters). 

E. virginicus (Sey. et Sad.) on Ostrya virginica. 

E. australis (Atk.) on Car pin us americanus. 

E. Jilicinus (Bostr.) on Aspidium sjnnrdosum. 

E. potentillae (Farl.) on Potentilla geoides, P. canadensis, P. 
sylvestris. 

E. githaginis (Bostr.) on Agrostcmma Githago. 

E. lutescens (Bostr.) on Polystichum Thelyptcris. 

E. umbrlliferarum (Bostr.) on Heraclcum Sphondylium, Pcu- 
cedanum palustre and P. Orcosclinum. 

E. ostryae (Mass.) on Ostrya carpinifolia (brown spots). 

E. betulae (Fuck.) on Betida verrucosa, B. pubcsccns, B. 
turkestanica (whitish spots). 

E. Jieivus (Farl.) on Betida populi/olia, B. yapyruera. 

E. accricolus (Mass.) on Acer campestre and A. /'seialo- 
platanus. 

E. fasciculatus (hag. et Sad.) on Nephrodium (whitish spots). 


The following are some of the more important species of 
Exoasceae : 

Exoascus pruni Fuck. (Pocket-plums). This attacks the 
ovaries of Primus domcstica (plum), P. Pad us (bird cherry), and 
1\ virgin iana, causing the mesocarp to grow rapidly, whereby 
the fruits increase in size and become much changed in form, 


THE PARASITIC EXOASCEAE. 


155 


while the stone, including the embryo, remains stunted. (Fig. 
49.) The “pocket-plums” (fools or bladder-plums) dry up, and 
remain hanging on the tree till autumn. De Bary found on 
the plum a withering of calyx and stamens resulting from the 
development of the hymenium of this Exoascus ; on the bird 
cherry, according to Magnus and AVakker, enlargement of the 
stamens occurs. Sometimes a considerable thickening and 
twisting of the young shoots takes place, and their leaves 
curl up. 



Fig. 48 . — Exoascus pruni. T wig of Plum, with four deformed fruits ; one 
normal plum is partially hidden, the other is in the middle, i natural size, 
(v. Tubeuf del.) 


The mycelium hibernates in the soft bast of the twigs, and 
proceeds thence in spring into young shoots and ovaries. 
According to De Bary, the infected ovaries double their size 
in two days, and are full grown in eight days. The asci form 
a close layer under the cuticle of the ovary, and finally 
rupture it. 



15G 


ASCOMYCETES. 


Exoascus Rostrupianus Bad. This fungus causes “ pockets ” 
on Prunvs spinosa (sloe) similar to the preceding species. 
According to Sadebeck, the asci in this case are more slender. 



Fio. 40 . — Bxoutcux / tru.nl . Malformed 
Plums— “ pocket plums"; one which is 
cut shows the rudimentary stone, 
natural size. (v. Tubeuf phot.) 



Fio. 50 . — Bxoatcut pruni on twig of Pruvttx 
Patlus ( at end of July) Four of the ovaries 
arc malformed, (v. Tubeuf del.) 



Fio. 61 . — BxoatcuM prvni. Young twigs of l’lum, showing effects of mycelium. 
The shoots arc swollen and distorted, one diseased leaf remains hypertrophied 
ami much crumpled ; on one spur a normal and a " pocket plum are borne. 
Specimens from the Museum at Golaenhoim. 1 natural sire. (v. Tubeuf phot.) 


THE PARASITIC EXOASCKAE. 


157 


Exoascus communis Sad. This produces pocket-plums on 
Primus americana, P. pumila, ctnd P. maritime t in America.' 

Similar “ pockets ” also occur on Primus subcordata, P. Chicasa, 
and P. pennsylvanica, in America, as a result of some Exoascus. 

Exoascus Farlowii Sad. produces similar 
deformation of carpels and floral envelopes on 
Prunus serotina in North America. 

Exoascus Johansonii Sad. produces carpel- 
enlargement on the female catkins of Populus 
trcmula, P. tremuloides and P. grandidentata ; the 
contents of the asci are yellow. (Fig. 52.) The 
anatomy of the deformed ovaries has just been 
described by Sadebeck. 1 

Exoascus rhizophorus Johan, causes similar fio. 52.— Exoascus 

Johansonii Sad. on 

enlargement of the female catkins of Populus Popuiustremuia. (v. 
alba. 

Exoascus alni-incanae Kuhn (Ex. amentorum Sad.) This 
species is readily distinguished by the absence of a stalk-cell 
on the ascus. It causes increased growth and enlargement 
of the seed-scales of alder catkins, the fruit itself being seldom 
attacked. The fleshy bladder-like outgrowths at first appear 
as little red processes ; later, the asci are developed on the 
outer surface as a whitish coating. On many of these red 
processes may still be recognized the trifid apex of the normal 
scale, (this is really formed from five smaller scales fused into 
a single large one with a trifid apex). A number of these 
red outgrowths are generally present on each infected catkin, 
yet the alders continue to flower vigorously every year. 

Wakker, 2 in investigating the anatomy of the deformed scales, 
found the following alterations : — the scales are increased to many 
times their original size and contain two cavities; all parenchy- 
matous cells become regular and iso-diametric ; lignification of 
the elements of the wood is more or less interfered with, and 
fewer wood-fibres are produced ; there is an accumulation of 
transitory starch. 

Exoascus alni-glutinosae Tubeuf. This is a new species 
distinguished by v. Tubeuf in 1895. It occurs in the Sudetic 
mountains, Italy, Denmark, and Sweden, on Alnus glutinosa. 
Its habit is similar to that of Ex. cdni-incanac, but the asci 
1 Sadebeck (See Literature), 4. p. 144. 2 Priwjsheim’s Jahrbuch, 1892. 



158 


ASCOMYCETES. 


contain only conidia, whereas those on Alnus-incana are said 
by Sadebeck to contain only ascospores, unless on very rare 
occasions. In the lower and higher Alps, although both species 
of alder are not infrequently found together, yet the Exoascus 
is found only on Alnus incana, and no species occurs on A. 
glutinosa. 


r 



— 


Fig. 53. — Bxoatrns alni-incanae in catkins of Ainu .< incana. Many of the scales 
arc developed as elongated red soft tongue-like structures, on which the asei are 
produced as a whitish coating, (v. Tubouf phot.) 


Exoascus epiphyllus Sad. (Ex. borcali s Job. 1 ) The witches - 
broom fungus of the white alder (Alnus incana.) 

The author 2 was the first to describe and figure this form 
of disease in 1884; and Sadebeck recently succeeded in pro- 

1 A". Sven. Vet. Akad. 18S!> and 1SS7. Tubeuf, /iotmi. Centralbl., ISSHi. 

- Tubeuf, Beitr&giz. Kenntniss d. Baumkrankhtittn, 1888. 



THE PARASITIC EXOASCEAE. 


159 



ducing the brooms by artificial infection of alder. The disease 
is common and epidemic, and a single tree may carry as many 
as a hundred brooms. 

The witches’ brooms are 
composed of many thickened 
twigs, beset with an abnor- 
mal number of lenticels, 
and the point of infection 
shows a distinct swelling, 
from which the broom tends 
to turn directly upwards. 

The leaves are somewhat 
modified, they are larger and 
thicker than the normal, 
they unfold later and wither 
earlier, while their stipules 
remain attached for some 
time. The brooms of alder 
only survive a few years, 
and by their decay cause 
the death of large branches, 
and frequently of the whole 
tree. 

The asci, which are sunk 
in a depression of their 
stalk-cell, form a w’hite 
coating on both surfaces of 
the leaves. The mycelium 
hibernates in the buds. 

Exoascus turgidus Sad. 
causes the formation of 
witches’ brooms on Betula 
verrucosa. The leaves form- 
ed on the brooms are some- 
what crumpled, and the asci 
are produced on their lower 
surface. 

Exoascus betulinus 

Rostr. produces witches’ 
brooms on Betula pubcscens and B. odorata. 


Fig. 54. — Exoascus epiphyllus. Witches’ broom 
in first year, showing swelling at the point of infec- 
tion. The leaves are already shed in autumn, while 
the normal still remain 4 natural size. After 
v. Tubeuf.) 


160 


ASCOMYCETES. 


* Witches’ brooms on birch are very common in Scotland. 
They appear as tangled masses of twigs, which at first sight 
give the impression of some bird’s nest. I have frequently 
examined the leaves borne on these brooms, and have never 
failed to find the asci of an Exoascus. Sadebeck gives in 
his monograph the two above-named species as found on birches 
bearing witches’ bi-ooms. Mites (e.g. Phytoptus) have also been 
given as the cause of these malformations. On close examination 
of brooms which undoubtedly bore Exoascus, I found that a 
broom results from a prolific development of small twigs on 
one or a few knotty swollen parts of a branch. Each central 



Fio. 55. — I Pitches Broom of Ike Hornlfcam. Eroascns carpini on Carpinus B> lulus. 

The bush measures about 1 metre across, and arises laterally from a branch, the 
upper normal part of which has been removed, (v. Tubeuf phot.) 

knot we may regard as the position of the bud which was 
first infected, and from which the broom system took its 
origin. As one result of the attack of the fungus, the greater 
number of the buds in the axils of the scales of the infected 
hud have grown out as twigs, but not into well-developed 
ones. In consequence, nearly every twig has been killed back 
by the winter, but not completely, so that from each twig- 
base has sprung a new crop of stunted immature twigs like 
the first, and equally liable to be killed in the following winter. 
Thus has arisen that tangled mass of dead or sickly birch 
twigs which we call a witches’ broom. [Edit.] 



THE PARASITIC EXOASCEAE. 


161 


Exoascus alpinus Johan, and Ex. nanus Johan. Both occur 
on Betula nana, and induce formation of hypertrophied twigs. 



Fig. 56. — Witches' Broom of the Cherry. Exoascus cerasi on Prunus Cerasus. The 
whole left side forms a large broom. A smaller example occupies the summit of 
the crown, while another hangs downwards to the right. In winter condition, 
(v. Tubeuf phot.) 


The mycelium of Ex. names hibernates in twigs, and penetrates 

L 


162 


ASCOMYCETES. 


into the inner tissues of newly-formed twigs and leaves. The 
mycelium of Ex. alpinus passes the winter in the buds, spreading 
thence in spring into young twigs and leaves. 



Fio. 57 . — Bxoatcas cerati on Prunu* Cti\uus. Cherry-tree In blossom, with the 
exception of four witches’ brooms. The tree is us yet leafless excopt the brooms, 
which are in full foliage and show up dark. (v. Tubeuf phot.) 


Exoascus carpini Rostr. is common on Carpi mix Bet ulus (horn- 
beam) (Fig. 55). The brooms produced are bushy and densely 
leafed ; the twigs are thickened and much branched ; the leaves 


THE PARASITIC EXOASCEAE. 


103 


are somewhat curled up, and the asci appear on their lower 
surface. 1 

Exoascus cerasi Fuck, occurs very commonly on cherry 
trees ( Primus Cerccsus and P. avium) both in Europe and America. 2 
It produces witches’ brooms, which may be large, upwardly 
directed, bush-like, and very conspicuous structures, with 
numerous thickened and elongated twigs (Fig. 3); or they may 
be small, hanging bunches of twigs with upturned free ends. 
The leaves are somewhat wavy, slightly crumpled, and reddish ; 
on their lower epidermis they bear asci, and fall off prematurely. 



Fig. 58. — Normal twig of Cherry from a tree in blossom, as in Fig. 57. 

(v. Tubeuf phot.) 

The brooms are visible at a considerable distance in the winter 
(Fig. 56), while they are even more conspicuous during the 
dowering season (Fig. 57). At the latter time, before the 
leaf-buds open, the cherry trees are normally covered with 
white blossom, while the brooms bear leaves only, and rarely 
blossom. Hence they produce little or no fruit. Each tree 

1 Wehmer (Bot. Zeitung 1896) discusses the formation of these witches’ 
brooms. (Edit.) 

- E. Rathay, “ Uber die Hexenbesen d. Kirsehbaumen.” — Sitzungsber. d. K. K. 
Akad. zu Wien. 1881. 


164 


ASCOMYCETES. 


may bear several brooms, and every tree in a fruit -garden 
may be attacked, so that this disease has assumed consider- 
able economic importance. As a preventive measure, the removal 
of all brooms at the time of pruning the trees is strongly 

recommended. 

[According to Shirai ( Tokio 
botanical magazine , 1 8 9 5) witches' 
brooms are produced in Japan 
on Prunus pseudo-cerasus, by a 
distinct species, Ex. pseudo- 
cerasus .] 

Exoascus minor Sad. This 

species induces hypertrophy of 

shoots of Prunus Cha m. nicer asus 

and P. Cerasus, but cannot be 

said to cause formation of 

witches’ brooms. The mycelium 

hibernates in the buds, and 

spreads only underneath the 

cuticle, while that of Ex. cerasi 

lives in the tissue of the twigs 

and leaves. It is characteristic 

of this species that only leaves 

here and there on a twig may 

Pio. .v.i. — Twig from witches' broom in be attacked, while their neigh- 
foliage, a* in Fig. r >7. Photographed at same . • 1 1 i \ \ 

time as Fig. Vs for comparison, (v. Tubeuf bOUTS rGHlfllll (JU1L0 llCflltliy J both 

rhot) Howers and fruit may also be 

borne. Diseased leaves appear much crumpled, and Sadebeek 
states they have an odour of cumarin ; they turn brown pre- 
maturely and fall off. 

Exoascus insititiae Sad. is found on Prunv* domrstica and 
/’. Insititia in Europe, and /'. pcnnsglvanira in North America. 
It causes formation of witches’ brooms smaller than those on 
the cherry tree, yet probably more common in the fruit garden. 
They bear no fruit, and are a source of considerable loss. 
The mycelium hibernates, like that of Ex. ccrasi, in the bark of 
twigs, and spreads in spring into the buds. 

The leaves of the host bear asci on the lower epidermis; 
they are always more or less curled up, and fall off early. 
To prune off all brooms is the best preventive measure. 




THE PARASITIC EXOASCEAE. 


165 


Exoascus deformans (Berk.) causes the “curl disease” of the 
peach (Prrsica vulgaris), and may inflict great injury. The 



Fig. GO . — Exoascus minor. Curl disease of Cherry. 


mycelium hibernates in bark, pith, and medullary rays of twigs, 
so that it reappears each year. An Exoascus, which occurs 



B 

Fig. 61 . — Exoascus deformans. Comparison of normal section of leaf of Prunus 
Persico with a hypertrophied one, B ; in the latter the mycelial hyphae have 
been slightly shaded. The sections are from different parts of the same leaf, and 
are drawn with the same magnification. (After W. G. Smith.) 


on the almond ( Amygdalus communis), resembles Ex. deformans 
so closely that they are now regarded as the same species. 



1G6 


ASCOMYCETES. 


This is supported by Smith’s investigations, in which an an- 
atomical comparison of diseased twigs of peach and almond 
showed no difference in the pathological effects. 

Exoascus crataegi Fuck, occurs on Crataegus Oxyacanilia , 
and causes red swellings on the leaves and flowers, accom- 
panied by hypertrophy of shoots in which the mycelium 
perennates. 

Exoascus Tosquinetii (West.). The deformation caused by 
this species is frequent on the black alder (A /nvs glutinosa). 
The thickened, elongated, wrinkled twigs render attacked parts, 
very conspicuous in contrast to the normally developed parts of 

the tree. The leaves may be 
wholly attacked and much 
enlarged, or they may only 
lie hypertrophied at places so 
as to form pustule-like swell- 
ings. The epidermal and 
mesophyll- cells of diseased 
leaves become greatly en- 
larged. 

Exoascus aureus (Pers.). 
The leaves of the black poplar 
(PopvJvs nigra ) attacked by 
this parasite exhibit pustules 
(Fig. (32). The asci are 
formed as a golden coating 
on the concave side of the 
pustules, which is, in most 
cases, the under side of the 
leaf, rarely the upper. The 
cells forming the pustules 
have thicker walls and a 
somewhat different shape from the normal epidermal cells, and 
they are not unfrequently sub-divided by walls of secondary 
origin (Fig. 63). 

According to Smith, the cells of the palisade parenchyma have 
also thickened walls, as well as being elongated and occasionally 
chambered ; the cells of the spongy parenchyma are enlarged and 
have thicker walls ; so also are the cells of the collenchymn of 
the leaf venation. 



THE PARASITIC EXOASCEAE. 


167 


Exoascus coerulescens (Mont, et Desm.) produces similar 
blisters on oak leaves. 



normal and hypertrophied tissue. The cells of the swelling are abnormally 
elongated with thickened walls, and some show secondary cell-division. The 
bases of the asci are wedged in between the cells ; one ascus is shown with 
conidia. (v. Tubeuf del.) 

Exoascus carneus Johan, occurs on leaves of Betula odorata, 
B. nana, and B. intermedia. The pustular outgrowths rise above 



Fig. 64 . — Exoascus carneus on Betula. i odorata. (v. Tubeuf del.) 



Fig. 66.— Section of leaf hypertrophied by 
attack of Exoascus carneus ; the asci of the 
fungus coat the upper epidermis. Drawn 
with the same magnification as Fig. 65, for 
comparison. (After W. G. Smith.) 


168 


ASCOMYCETES. 


the upper surface of the leaf (Fig. 64), and the upper epidermis 
alone bears the asci. In the pustules, the leaf may be two to 
four times as thick as healthy parts. The greatly increased 
thickness is due for the most part to enlargement of the cells 
of the mesophyll, while at the same time their normal arrangement 
is completely lost (Figs. 65, 66). The elements of the libro- 
vascular bundles are enlarged ; the cells of the upper epidermis 
are more numerous, contain a reddish sap, and their walls are 
thickened. All chlorophyll is destroyed in the pustules. 

Ex. polysporus (Sor.) causes swollen 
spots on leaves of Acer tartaricum. 

Ex. bullatus (Fuck.) causes similar 
spots on leaves of pear ( Pyrus 
communis) and quince ( Cydonia 
japonica). 

Ex, Sadebeckii (Johan.) causes 
simple spots on leaves of Alnus 
f/lutinosa. 

Many other species, named in our 
list and in Sadebeck’s papers, will be 
found described in detail in one or 
other of the papers already cited. 

B. C<\RroAsci. 

( Ascomycetes with Sporvcarps.) 

The asci of the Carpoasci are not 
formed directly on the mycelium, but 
from a special part of it, which 
becomes more or less enclosed in 
another non-ascogenous portion. From 
these two portions of the mycelium a sporocarp is formed, in 
which we can distinguish three distinct constituents : (a) the 
envelope containing (b) the paraphyses and (c) the asci. 
Amongst the Gymnoasci the envelope, if present, is never 
more than a loose hyphal tissue, but in the Carpoasci both 
paraphyses and envelope are present, the latter with char- 
acteristics distinctive of each species. The sporoearps of the 
lower Carpoasci are completely closed structures containing 
only one or a few asci ; those of the higher forms, however, 



Fig. 07.— Esooacu* poh/Aporu* on 
Acer tartaricum from Sweden. The 
attacked leaf shows pale spots with 
brown centres. The former result 
from the Taphriyta, and are covered 
by a white coating of asci ; the brown 
sjxjts are produced by other fungi 
which grow on the spots already 
killed. J nat. size. (v. Tubeuf del.) 


CARPOASCI. 


169 


contain many asci, and the envelope is pierced by a definite 
aperture. 

Brefeld endeavours to explain the ascocarp of the Erysiplieae from the 
sporangia! structures of tlie Zygosporeae ( Rhizopus and Mortierella) ; De 
Bary 1 and Zopf, 2 on the other hand, see in it an oosporangium, like that 
of the Oosporeae. Under this latter view the envelope of the Carpoasci is 
morphologically homologous to the antheridia of the Saprolegnieae and 
Peronosporeae. In the latter group the antheridium generally takes the 
form of an open fertilization-tube, in the Saprolegnieae it remains closed, 
and is physiologically no longer an antheridium. Zopf found in one of 
the Saprolegnieae ( Dictyuchus carpophorm), an envelope resembling that 
of tlie Erysiplieae, and on this ground he, along with De Bary, links the 
Erysiplieae to Oomycetes like Achyla through forms like Podosphaera. 

The reproductive cells or ascospores result from direct nuclear 
division inside the asci. They are generally simple and uni- 
cellular, but it is not uncommon to find that, by the formation 
of cross and longitudinal walls, each spore forms a cell aggre- 
gation (sporidesm of De Bary), with each cell capable of 
germination on its own account. The number of cells in each 
aggregation, as well as the size and shape of each cell, are in 
many cases constant, and form points for the determination of 
species. Appendages to the spores are characteristic of many 
species. 

The Carpoasci possess, in addition to ascospores, other 
means of reproduction. Thus, thick-walled chlamydospores occur 
either in the mycelium as resting-spores ( Hypomyces ), or as 
spores (oidia) resulting from a breaking-up of hyphae. 
Many kinds of eonidia may also be produced, some from the 
germinating ascospores, some abjointed from a branch of the 
mycelium or from some form of special conidiophore. These 
latter may be produced isolated, or massed together in hollows 
of the stroma, or in closed structures resembling ascocarps, 
and called pycnidia. The various forms of reproductive organs 
presented by each species will be more closely considered as 
we proceed. 

Tlie Carpoasci are arranged, according to the structure of 
the ascocarps, under the following divisions : — the Peris- 
poriaceae, Pyrenomycetes, Hysteriaceae, Discomycetes, and Hel- 

1 De Bary. Beitrage z. morph, it. Physiol, d. Pilze. 

2 Zopf. Beitrage z. Physiol u. morph, neider Organismen. Heft 3, 1S93. 


170 


ASCOMYCETES. 


vellaceae. All these groups include forms parasitic on plants, 
except the last, which is saprophytic. 

Gymnoascus and Ctenomyces are forms intermediate to the 
Gymnoasci and Carpoasci ; they have the asci enclosed in a 
slimy envelope of mycelial tissue. AVe place them along with 
the former group, although Brefeld puts them in the latter. 

PERISPORIACEAE. 

The Perisporiaceae are distinguished by having an ascocarp 
or perithecium which never opens, so that the asci are only 
exposed by decay of the envelope. It includes three families, 
the Erysipheae, Perisporieae, and Tuberaceae. 

ERYSIPHEAE. 

The members of this family all live as parasites on the 
outer surface of plant-organs, and have a much-branched, 
white, septate mycelium, which derives nourishment from the 
interior of the epidermal cells of the host by means of 
haustoria of various forms. 

The Erysipheae or Mildews appear as white spots and 
coatings, on which the ascocarps or perithecia appear later as 
black points. On microscopic examination, the perithecia 
will be found to contain one or many asci, while externally 
they are beset with thread-like appendages of a definite form 
and definitely arranged, so that they are of great use in 
determining the various species. 

The fungus passes through the winter by means of the 
ascospores. These do not ripen till spring, when, liberated by 
decay of the ascocarp, they are carried to plants, where they 
germinate, especially on the leaves, and form a mycelium. In 
addition, the fungus is propagated throughout the summer by 
means of conidia produced on special conidiophores in acropetal 
series or chains, of which the distal terminal conidimn (acrospore) 
is the oldest and largest. The ripe conidia fall oil' and 
produce a mycelium which is at once fixed in place by the 
formation of haustoria. 

Prevention. “Sulphuring” is the method chiefly used for 
combating mildew. This consists in dusting powdered sulphur 
(flowers of sulphur) over the plant threatened with attack. 


ERYSIPHEAE. 


171 


The operation is done by hand or by special implement. One 
of the best known of these is the “ Sulphur Puff.” This 
consists ot a brush with a hollow stem to contain flowers of 
sulphur, the end of the stem being perforated to allow the 
sulphur to escape on to the plant. Sulphuring must be 
carried out during dry weather to prevent the powder being- 
washed away. It has also to be frequently repeated, so that 
young growing shoots, flowers, fruits, leaves, and all parts 
liable to attack, may be kept well dusted. Sulphur prevents 
germination of conidia on the leaves; it also kills the 
mycelium, while the plant itself remains uninjured. 

Besides sulphuring, various copper solutions give very good 
results, while at the same time they act as a preventive 
against the false mildews ( P/asmojuira , Peronospora, etc.). 

Sphaerotheca. 

Perithecia spherical with thread-like appendages; they contain 
one spherical ascus with eight colourless oval ascospores. 



Fig. 68. Rose-mildew. Sphaerotheca. pannoso. The fungus forms a white mealy 
coating on the leaf, especially on the lower side ; the leaves are also more or less 
curled up. (v. Tubeuf phot.) 


172 


ASCOMY CETES. 


Sphaerotheca pannosa Wallr. (Britain and U.S. America). 
The Rose-mildew. The mycelium forms a thin white coatiDg on 
the leaves, and is nourished by lobed haustoria inserted into 
the epidermal cells. Young leaves or buds when attacked 
become more or less deformed, their function is interfered with, 
and death may result. In this way great damage is done in 
rose-gardens. This parasite also attacks young leaves and fruits 
of peach and apricot. 



Fin. 00. — Sphaerotheca /M.ihiosti on Peach. The mycelium and conidiophores 
arc shown on the epidermis of a leaf. (After Tulasne.) 


Rose-mildew is propagated during summer by ovoid, uni- 
cellular conidia abjointed in acropetal series from erect conidio- 
phores. The perithecia have short simple appendages, and 
contain elliptical spores. 

The disease may be combated by “ sulphuring according to 
l\itzema-Bos, spraying with Bordeaux mixture has also shown 
good results. 



Sl’HAEROTHEt'A. 


173 


Sphaerotheca (Podosphaera) castagnei Lev. (Britain and 
U.S. America). The Hop-mildew. The mycelium is found on 
all parts of hop-plants, causing considerable damage, especially 
when it attacks the young inflorescences. The perithecia have 
recumbent, brown, simple appendages. This species appears 
chiefly on various Compositae, Eosaceae (esp. Spiraea Ul. maria), 
Cucurbitaceae, Geraniaceae, etc. Sorauer reports it as very 
injurious to apple-trees. 



Fig. 70.— Sphaerotheca castagnei on Spiraea Ulmaria. The white mycelial coating 
covers every part of the inflorescences. Two specimens are much less deformed 
than the others, (v. Tubeuf phot.) 

Oidium farinosum Cooke. Attacks young leaves and calyx 
of apple; it is easily distinguished from the oidium- condition of 
the preceding species. 1 

Sph. mors-uvae B. et C. The Gooseberry-mildew. Is specially 
injurious to Bibes Uva, crispa and other species of Bibes in 
America. Spraying with a solution of potassium sulphide (h oz. 
in 1 gallon water) at intervals of twenty days is recommended. 2 

1 Sorauer, Hedwiyia, 1889. 

- Halsted {U.S. Department of Agriculture, Report for 1887) describes this 
disease (Edit.). 



17 + 


ASCOMY CETES. 


Sph. epilobii Lk. occurs on Epilobium (U.S. America). 
Sph. Niesslii Thiim. on Sorbus {Pyrus) Aria. 

Sph. pruinosa C. et Pk. on Rhus in America. 



Fio. 71 .—Sphaerothtca castagnei. Epiphytic mycelium on epidermis of Spiraea 
Ulmaria. Three haustorta are embedded in epidermal cells. Two conldiophores 
are shown, from one of which a conidium has become detached. A hair of 
Spiraea is shown at one side. (v. Tubeuf del.) 


Podosphaera. 

This genus is distinguished from Sphaerothcca by its upright 
perithecial appendages, which branch dichotomously towards their 
extremities. 

Podosphaera oxyacanthae I>. C. Apple powdery mildew, 
also occurring on pear ( Pyrus ), hawthorn {C rat a eyas), mountain 
ash ( Pyrus Aucuparia), and medlar {Mrspilus). In America 
this disease is very injurious to apple-cultivation . 2 It attacks 
chieHy young seedling plants, stunting their growth and causing 
them to lose their leaves. 

P. tridactyla Wallr. This causes injury to leaves of various 
species of Primus (cherry, plum, and sloe ) 3 (Britain and U.S. 
America). 

-Account by M. B. Waite (U.S. Department of .hjr (culture, Report for 
1S88); notes on treatment in Fairchild’s experiments (Journal of Mycoloyy, vn. 
p. 256), and elsewhere (Edit.). 

1 Halsted Zt itsckrifl f. Plianzeidrankheiten, 1895, p. .'CIS) gives as additional 
hosts: Apple, Crataeyu-i Oxyaeantha, Amelanchitr canei’/e mis and Spiraea (Edit.). 


PODOSPHAERA. 


175 


P. myrtillina Schub. on leaves of V actinium Myrtillus (bil- 
berry), V. uliginosum, and Empetrum nigrum (crowberry), (U.S. 

America). 

Erysiphe. 


The perithecia contain several asci, each with two to eight 
oval hyaline spores. The appendages are like these of Sphae- 
rotheca, simple and thread-like. 

Erysiphe graminis D. C. Mould or mildew of grass and 
wheat. Grass and cereals, especially wheat, often suffer serious 
damage from this parasite. The mycelium appears on the leaves 
as white or brownish spots, generally on the upper surface. 
Colourless conidia ( Oidium monilioides, Lk.) are produced acro- 
petally in chains. The somewhat rare perithecia have brown 
appendages, and contain eight to sixteen asci, with four to 
eight spores each ; the spores mature in spring as the dead 
leaves lie on the ground. This mildew has inflicted great 



loss both in Europe and America. Dusting the threatened 
crop with “ flowers of sulphur ” will 
probably check the first stages of an 
attack, but care in destroying infected 
crops is by far the most effective 
preventive. 

Erysiphe martii Lev. This fre- 
quents various Leguminosae (clover, 
beans, vetches, peas, lupines, etc.), 

Cruciferae, and other plants (Britain 
and U.S. America). 

Er. umbelliferarum De Bary. 

Occurs on various Umbelliferae 
(Britain). 

Er. communis Wallr. on tobacco, also on various Banun- 
culaceae, Papilionaceae, etc. (Britain and U.S. America). 

Er. tortilis Wallr. on Cornus sanguined (Britain and U.S. 
America). 

Er. galeopsidis D. C. on Labiatae (Britain and U.S. 
America). 

Er. cichoriacearum D. C. on Compositae, Boragineae, and 
also causing considerable damage to cucumbers (Britain 
L T .S. America). 


Fig. 72 . — Eiysiphe umbelliferarum. 
Germination of a conidium (sp) on 
Anthriscus sylvestris. An attach- 
ment-disc has been formed, and a 
e:erm-tube has penetrated the epider- 
mis to become the first haustorium. 
(After De Bary.) 


and 


1 7 G 


ASCOM YCKTKS. 


Microsphaera. 

The perithecia contain several asci with two to eight spores, 
and the appendages have dichotomously branched ends like 
those of Podosphaera. 

Microsphaera astragali 1). C. Occurs on Astragalus glycy- 
phyllos and A. virgatm (Britain and U.S. America). 

M. berberidis D. C. on Barberry (Britain). 

M. lonicerae D. C. on species of Lonicera. 

M. grossulariae Wallr. on Gooseberry (Britain and U.S. America). 

M. lycii Lascli. on Lycium, and Desmodium (Britain and U.S. America). 
M. evonymi 1 ). C. on Evonymus europaeus (Britain). 

M. alni D. C. on Alnug glutinosa , Betula verrucosa, and II. pubesccns. 
Ithamnus cathartica, Viburnum Opulus, and I'. Lantana, etc. (Britain and U.S. 
America). 

M. densissima (Schwein.) 1 . This species forms orbicular patches on the 
leaves of (Juercus tinctoria, etc., in North America. 

M. Guarinonii Br. et Cav. on Cystisns Laburnum. 

Also several other American species. 


Uncinula. 

The perithecia contain several asci with two to eight spores. 
The appendages have involute ends, and are simple or dicho- 
tomously branched. 

Uncinula spiralis B. and C . 2 (U. S. America and Britain). 
The Vine Mildew. This disease was first observed in England 
in 1845, and since then has spread over the whole of Europe. 
The conidial stage has caused widespread injury, but the perithecia 
remained quite unknown till 1892, when they were observed on 
vines in France by Couderc. and in 1893 in large numbers by 
Viala. In America, a similar disease is also well known ; its 
perithecia have been long recognized and named Unciunlu 
spiralis. The identity of the American and European mildew 
was first suggested by Viala in 1887, and may now be assumed. 
The perithecia 3 when mature arc brown, spherical, and beset with 

1 Atkinson, Bulletin of Torrey Botanical Club , Dec, 1894. 

'-In consequence of recent investigations, this species has been transferred from 
the genus Erysiphe, and revised with the author's consent. (Edit.). 

Viala, Compt. rend, rxix, 1894, p. 411. Prillieux, Bull, dt la Soc. mycol. </< 
France, 1893. 

;l B. T. (ialloway (Botanical Gazette, 1895, p. 480), gives a recent account of 
the development of this Uncinula. (Edit.). 


UNCINULA. 


177 


appendages having hooked tips. Within the perithecia are 
found the ovoid asci containing the spores ; there are from four 
to ten asci in each peritheeium, and four to eight spores in each 
ascus. 

The conidial stage was formerly known as Oidium Tucker i. 
The conidia are abjointed as oval colourless bodies from simple 
septate conidiophores, to the number of two or three in each chain. 
They germinate at once, and as they are formed in large numbers, 
especially in moist weather, the disease spreads rapidly. The 
mycelium is non-septate, or almost so, and attaches itself to the 
epidermal cells of vine-leaves and young grapes, by lobed attach- 
ment-discs, from which simple sac-like haustoria make their way 



Fig. 73 .— Uncinula aceris. Perithecia. (After Tulasne.) 


into the cells. The mycelium forms white spots, but after a 
time causes the death of cells near it, so that brown withered 
spots appear. The leaves generally wither, the grapes, however, 
continue to grow at the places not attacked, till rupture of the 
coat ensues, then they shrivel up or fall a prey to mould-fungi. 
Sulphur is the preventive generally used (See p. 170). 

Uncinula aceris D. C. (Britain). This appears as white spots 
on the leaves of species of Acer, native and cultivated. When 
attacked by this mildew, young unfolding leaves are stunted in 
growth, while older leaves in autumn still retain their chloro- 


178 


ASCOMYCETES. 


phyll in diseased spots, so that when dead and yellow, they 
are still spotted with green. The conidia are oval, so also the 
spores of which six to eight are found in each ascus. 

U. Tulasnei Fuck, produces 
a white coating over the whole 
leaf-surface of Acer platanowLes. 
The conidia are spherical. 

U. circinata C. et Peck, is 
found on species of Acer in 
America. 

U. salicis D. C. (Britain and 
U.S. America). This species 
occurs on leaves of the willow, 
and produces white spots or 
thick coatings on one or both 
surfaces. It is also found on 
leaves of poplar and birch. 

U. prunastri D. C. on Prunus spinosa (Britain). 

U. Bivonae Lev. on Ulmus montana (U.S. America). 

Also other American species. 

Phyllactinia. 

The spherical perithecia are flattened at the poles, and 
enclose several asci containing two or three oval sulphur-yellow 
spores. The appendages 
are sharp-pointed hairs 
with swollen bases. 

Phyllactinia suffulta 
Ifebent. (Ph. guttata 
Wallr.) produces white 
spots or coatings on the 
leaves of many trees, e.g. 
beech, hornbeam, ash, 
birch, hazel, oak, etc. 

(Britain and U.S. 

America). 

PERIS PORI EAE. 

The Perisporieae include the following genera Thiel avia. Divu- 
Tosporium , J Tagnusia , Ccphalothcca, Zopjiclla, Aui.i'ia, Kurotium, 



Flo. ~&.--PkyUactinia tuff'ulla on Fat tu tylcatica. The 
leaf Is partially covered l*y a white mycelium, on which 
the perithecia appear as black points. lv. Tubeuf del.) 



Fio. 74. — Uneinula ttdicit. Perithecium. 
(After Tulasne.) 


PEEISPORIEAE. 


179 


Aspergillus, Penicillium, Zopfia, Pcrisporium, Lasiobotrys, Apio- 
sporium, Capnodium, Asterina, Microthyrium. 

To this sub-division of the Perisporiaceae belong some com- 
mon forms of mould-fungi which are generally only saprophytic, 





Fig. 76. — Phyllactinia suffulta from Beech. Perithecium, with characteristic 
appendages. Contents of the perithecium : asci, spores, and chains of cells 
resembling parapliyses. (v. Tubeuf del.) 


but occasionally find their way into fruit with broken epidermis. 
They are thus found carrying on secondary decay and rot, where 
other diseases have begun the attack. 


180 


ASCOMYt KTES. 


In this group are included certain species of fungi which are 
aide of themselves to induce rot in ripe fruit. Davaiue 1 was 
the first to direct attention to these, and recently they have been 
made the subject of very searching investigations by Wehmer . 2 
According to this author, only a limited number of species of 
fungi accompany this kind of rot and give rise to it primarily. 
As a rule they effect an entrance by some wound, possibly also 
through lenticels or other apertures. Some forms prefer certain 
species of host-fruit, in some cases even certain varieties. 

Wehmer gives the following synopsis : 


Fruit. 
Apple, | 
Pear, 
Medlar, j 

Grape, - 
Plum,- - 


Cause ok Ripe-rot. 

| Penicillium glaucum. 
■ Mucor piriformis. 

I ( Mucor stolonifer.) 
f Penicillium glaucum. 
1 Botrytis cinerea. 
f Mucor racemosus. 

I Penicillium glaucu m . 


Fruit. Cause ok Ripe rot. 


Orange, 
Citron, 
Mandarin, 
Cherry, - 

Walnut, - 


f Penicillium italicum , 

J Penicillium ol iraceum. 

- - Penicillium glaucum. 

Botrytis cinerea. 

Pen icillium glaucum. 


He then arranges them according to their occurrence, beginning 
with the most frequent : 

Penicillium glaucum Link. : on stone-fruits, pome-fruits, grapes, 
walnuts, especially common on apples. 

Penicillium italicum Wehmer : on southern fruits, c.g. citron, 
orange, mandarin. 

Mucor piriformis Fisch. : on pome-fruits, particularly on pears. 

Bolrytis cinerea Pers. : on grapes and walnuts. 

The following are less common species: 

Penicillium olivaceum Wehmer : on southern fruits. 

Mucor racemosus Fres. : on plums. 

Mticor stolonifer Ehrenb. : on apples. 

Pipe fruit should be so treated as to remove risk of infection as 
much as possible. This is done by storing the fruits in airy, dry 
places, and in loose contact with each other. A damp atmosphere 
promotes infection and facilitates the progress of rot. All decaying 
fruit should be separated at once, and valuable fruits are best 
isolated by wrapping singly in tissue paper before transportation. 


1 Davaine, “ Recherches sur la pourriture des fruits et des vegetaux vivants," 
Compt. rend., lxiii., ISfiG. 

-Wehmer, Beitrdge Kenntniss einheimischrr Pil-.i, Jena (Fischer), l$9, r >. 


PERISPORIEAE. 


181 


Species of fungi included in this group are the cause of 
those black, sooty coatings found on leaves frequented by green 
fly (Aphis) and other leaf-insects. These are purely epiphytic 
and saprophytic forms which derive nourishment from the 
‘'''“honey-dew” excreted by the insects. 1 They multiply very 
rapidly, and soon form dark coatings on the upper side of 
leaves and twigs. Little damage need be feared, since the 
leaves retain their green colour, and the coating is not enough 
to stop access of light. Amongst them are species of Cap- 
noclium, Meliola, and Apiospormm, as well as the conidial forms 
Fumago, Torula, Antennaria. 

The modes of reproduction of these forms are exceedingly 
varied. According to Zopf 2 they form : (1) ascocarps; (2) many- 
celled large conidia; (3) unicellular, very small conidia ; (4) 
isolated and clustered conidiophores ; (5) gemmae; (6) buds in 
a yeast-like manner ; while every fragment of a mycelium can 
produce a new growth. Any of the species may frequent 
many various plants, and can pass easily from one host to 
another. Some of the better-known forms are : 

Capnodium salicinum Mont. (Britain). This occurs on 
species of willow, poplar, hop, and many other plants. 

If it appears early and abundant on hop it may cause 
•considerable damage. (Fumago vagans is a conidial form). 

C. quercinium Pers. on oak. (U.S. America.) 

C. taxi Sacc. et Roum. on Taxus. 

C. foedum Sacc. (spermogonium form — Chaetophoma foeda ). 
On the leaves of oleander. (U.S. America.) 

The genus Apiosporium forms similar sooty coatings. 

A. pinophilum Fuck. This covers with a black coating 
whole twigs and leaves of silver fir; the needles however retain 
their green colour completely. ( Antennaria and Torula are 
forms of this.) 

A. rhododendri Fuck.; A. ulmi Fuck. ; and other species. 

The conidial form Pellicularia which produces grey coatings on the coffee- 
plant is considered among the Hyphomycetes. 

Species of Meliola also produce sooty coatings. 

M. citri Sacc. and M. Penzigi Sacc. occur on Citrus in 

1 Bitsgen, Der Honigthau. Biolcnjische Studien an Pflanzen. Jena (Fischer). 

-Zopf, “Die Conidienfriichte v. Fumago.” Xova acta, Bd. 40. Also: Zopf, 
Die Pilze ; Tulasne, Select, funrj., ill. 


182 


ASCOMYCETES. 


Southern Europe and America. Sooty mould of the orange is 
also ascribed to Capnodium citri Berk, et Desm. 1 

M. camelliae Catt. on Camellia japonica. According to 
Briosi and Cavara, this causes drying up of the leaves. 

Stemphylium ericoctonvm Br. et Bary, the “ sooty -dew ” of indoor heaths- 
is considered amongst the Hyphomycetes. 


Lasiobotrys. 

L. lonicerae Kunze. 2 The perithecia form black masses on 
green leaves of species of Lonicera. If these be removed the 
epidermis remains uninjured, except for a slight cavity with a 
lighter green colour than the neighbouring surface. 

Thielavia 

Perithecia spherical and without an aperture. The asci 
contain eight brown unicellular spores. Paraphyses absent. 
Conidia and chlamydospores are formed. 

Thielavia basicola Zopf. 3 This is the only species of the 
Perisporieae which causes a really serious plant-disease. It is 
allied to the Erysipheae, and produces three kinds of repro- 
ductive organs on the underground parts of plants of Lupine: 
(1) Cylindrical, delicate, hyaline chlamydospores, produced in 
pistol-shaped branches of the mycelium. (2) Thick- walled, 
brown-coated, resting conidia arranged several in a row, like 
spores of a phragmidium. (3) Perithecia, or little, spherical, 
permanently closed, brown structures with ovoid asci containing 
eight brownish lemon-shaped spores. 

A white coating of the hyaline conidia is first formed, then 
a brown coating of the dark conidia, and finally perithecia. 
The mycelium bores through the cell-walls and tills first the 
cells of the cortex, later those of the deeper parenchyma of the 
host-root. The disease of the root soon causes a stunting of 
the shoots and leaves, finally death of the plant. The roots 
attacked are at first brown, then they rot and become detached. 

1 W. (i. Fallow, liueeey Institute, i. 1876, p. 404 : Swingle and Webber. 

“Diseases of citrous fruits," U.S. I)ept. Agric. B till. 8. 1S!H>. 

2 Jaczewski includes Lasiobotrys with the Cucurbitariactai. 

■'Zopf, “ Ueber die Wur/.elbraune d. Lupinen.” Ze it nr It rift f. Pflanttnhmnk- 
lieite.it, I. p. 72. 


THIELAVIA. 


183 


The fungus has been observed on Lupinus angustifolius, L. albus, 
L. thermis, Trigonella coerulea, Onobrychis Crista galli, Pisum 
sativum, Senecio elegans, and Cyclamen} 

Thielaviopsis ethaceticus Went . 2 has been given as the cause 
of a sugar-cane disease in Java. 

The Tuberaceae form a third sub-division of the Perisporiaceae. 
The group includes the Tubereae and the Elaphomycetes. It 
contains no forms injurious to plants. 

In investigating Elapliomyces granulatus and E. variegatus, 
Reess 3 found that it not only formed mycorhiza, but was also 
parasitic on the roots of Finns and destroyed them. 


PYRENOMYCETES. 

The ascocarp or perithecium of the Pyrenomycetes is a closed 
structure provided with an opening by which the ascospores 
are discharged. The ascocarp of the Perisporiaceae, as has 
already been pointed out, has no such opening. The inner wall 
of the perithecium is clothed with («) the asci, (b) delicate fungal 
filaments. Of the latter, those in the depth of the perithecium 
are known as paraphyses, and among them the asci originate ; 
others around the sides and opening of the perithecium are 
the periphyses, which grow inwards so as to close both pore 
and canal. Perithecia may occur isolated or massed together, 
and are frequently sunk in a special cushion of fungoid tissue, 
the stromata. 

The Pyrenomycetes may also produce chlamydospores and 
various forms of pycnoconidia and free conidia ; these also are 
frequently developed on special stromata. According to Brefeld’s 
researches, the structures so well known as spermogonia with 
their contained sperinatia are only pycnidia containing conidia, 
which have in many cases been artificially caused to germinate. 

The Pyrenomycetes include a large number of forms par- 
asitic on all parts of living plants, most of them are capable 
of existing for some part of their lives as saprophytes, and as 

'This fungus is described as causing a root-rot of Viola odorala in U.S. 
America (Connect. Agric. Exper. Stat. Report for 1891). (Edit.) 

2 Went, Archie/ voor de Ja va-Suikerind us trie. 1893. 

3 Reess and Fisoh., “ Untersuch. iib. Ban u. Lebensgeschichte d. Hirschtruffel.” 

Bibliotheca botan. Heft 7. 1887. With Illus. 


184 


ASCOM Y 1,'ETKS. 


a rule they reach maturity only on the dead remains of host 
plants. Many of them are enemies of woody plants, and the 
mycelium of some can live in the elements of the wood itself, 
hence they constitute a dangerous group of wound parasites. 

The Pyrenomycetes may be sub-divided thus : 

1. The Hypocreaceae having soft coloured perithecia often 
placed several together on a stroma. 

2. The Sphaeriaceae with firm dark-coloured perithecia 
frequently embedded in a stroma. 

The Dothideaceae with perithecia so embedded in a 
stroma that they have no distinct wall of their own. 

All three divisions include forms parasitic on plants. 

(1) HYPOCREACEAE. 

The Hypocreaceae consists of a single family bearing the 
same name. Of the seventeen genera contained therein only 
six contain plant parasites, viz. : — Gibbcrdta, Calonectria, Nectria 
( including Ncdridla), Polystigma, Epichloe, Claviceps. The re- 
mainder are saprophytic only, and do not come within the 
scope of the present work : they are — Melanosjmra, Sdinia, 
Ehatheronnyccs, Hyponiyces, Sphacrostilbc, Ldcndrara, II ypocrca, 
Pleonedria. Barya, Oomyccs, and Conlyceps. 

Gibberella. 

The perithecia have a transparent blue or violet colour, and 
form tufts on the stromata. A stroma is not present in all 
the species. The spores are light-coloured, and spindle-shaped 
or oblong. 

G. moricola C’es et de Not. Passerini gives this as the cause 
of a disease of young twigs of mulberry. 

G pulicaris (Fr.) is very frequently found on trees. (Britain). 

Calonectria, 

The perithecia are yellow or red, and occur isolated or several 
together. The asci contain spores composed of three or more 
cells, rarely of one cell. 

C. pychroa Desm. causes death to young leaves of planes 
(esp. 1\ occifb'ntalis) ; it also multiplies by means of conidia 
( Fuse ri u m pb i tu n i). 


NECTRIA. 


185 


Nectria. 

Perithecia yellow or red in colour, and generally produced 
in close tufts on stromata of the same colour. The asci con- 
tain eight bicellular spores and few or no paraphyses. Conidia 
•of various kinds and shapes are also produced. 

Nectri^a cinnabarina Fr . 1 (Britain and U.S. America). The 
bright-red, button-shaped conidial cushions of this fungus may 



Fig. 77 . — Nectria cinnabarina , with peri- 
thecia on the dead bark of a still-living 
stem of Elm. Infection has evidently 
began at the wound of a cut branch near 
the middle, and extended outwards, (v. 
Tubenf phot.) 



Fig. 78. — Nectria cinnabarina. Portion of 
branch (magnified). Light-coloured cushions 
of conidiophores with conidia are breaking out 
towards the upper end, and colonies of hard 
red perithecia towards the lower end. (After 
Tulasne.) 


be found almost at any time on the dead branches of many 
deciduous trees, c.g., Acsculus, Acer, Tilia, Morns, Ulmus, etc.; 
also on Lonicera, Sambucus, Robinia, and Pyrus, in America . 2 

1 Tulasne, Select funtj., 1865. 

2 Behrens (Zeitsch. /. Pflanzenkrankheiteii (1S95) ascribes to Nectria the very 
common tuberous swellings on the twigs of A hies balsamea ; these, however, 
may arise without the agency of the fungus. 


186 


ASG'OMY CKTES. 


The dark-red masses of thick-coated, warty perithecia appear 
in autumn and winter on the dead branches only ; the asci 
•contain eight bicellular hyaline spores which germinate 
directly to form a mycelium. Infection of a new host-plant 
is effected by the mycelium, which enters by open wounds into 
living branches ; it is quite unable to penetrate the living 
bark and is dependent on wounds. The mycelium spreads 

rapidly through the tissues of 
the host, especially through the 
vessels of the wood ; the cam- 
bium and rind are not attacked 
directly, but are killed in conse- 
quence of the destruction of the 
wood . 1 The x-egions attacked 
in the wood appear as greenish 
stripes, and withering of leaves, 
followed by death of branch 
after branch, results in conse- 
quence of the growth of mycelium 
in the water-conducting elements 
of the wood. 

For protection against this 
and all other parasites, which 
find entrance by wounds, it is recommended to prune or dress 
trees only when necessary, and to paint all wounds with tar 
or tree-wax. This Ncctria is one of the commonest parasites 
of our parks and fruit gardens, hence all blanches already 
attacked should be removed and burned, likewise all blown 
timber which might serve as a nursery for production of 
spores or conidia. 

Nectria ditissima Tul. (Britain and U.S. America). This 
is a common parasite and a frequent cause of the canker of 
beech, apple, and other tiees . 2 The mycelium lives chiefly 
in the bark, causing it to die and form cracks. Under 
ordinary conditions all cracks and fissures are occluded or 



Flo. 79. — Ntctrio. cinnabarina . enlarged 
section of perithccial colony. Germinating 
ascospores. (After Tulasne.) 


1 Mayr in Hartig’s Unltrxurhuwjtn a. d. /brnt-holan.' Jimtitut zii Aliinchen, m. 
Berlin, 1SS*2. Brick, Arbeiten il. hoi an. J/iwimis, Hamburg, 189*2. 

Wehmer (Zeit*c h. f. Pfla n zr nlrati kh t itrv , 1894 sinl 1895), opposes Mnyr's con 
elusions and holds that Xerlria can penetrate intact, living bark. 

s Goethe, “ Ueber Krebs d. Apfelbiiume.” Rhein, litall f. Ohs/.. H i in, u. Gar- 
lenbau, 1879. R. liartig, Uultrtaich. atm d. forst-botan. hmtitut. ru Munchen. l. 


NECTRIA. 


187 


grown over in course of time by the activity of neighbour- 
ing living tissues, but the rapid development of the mycelium 
of this Nectria prevents any such healing, and brings about 
death of more bark. As a result the so-called “ cankers ” are 



Fig. 80. — Nectria ditissima. Canker Fig. 81. — Nectria, ditissima-. Canker on Hazel. The 

on a stem of Beech, (v. Tubeuf place of infection, a partially broken branch-fork. 

phot.) 

produced. The mycelium at first gives off tiny unicellular 
conidia on the bark, then later white cushions bearing fine 
conidiophores, from which are abjointed multicellular conidia, 
shaped like a sickle. Infection is brought about by the 
germination of spores or conidia on wounded parts of the 


188 


ASCOMYCKTES. 


bark , 1 and even on young unfolding leaves. The red lemon- 
shaped perithecia break through the bark as compact patches. 
They are distinguished from the perithecia of N. cinnabarina 
by their smooth exterior and their smaller asci and asco- 
spores. 

Combative measures to be used are plentiful dressing of 
wounded places with tar, and the burning of all infected 
material. 

Nectria cucurbitula Fr . 2 (Britain and U.S. America). This 
parasite on conifers generally, is particularly injurious to spruce 
( Picea ). It enters the host by wounds, such as those caused 
by the caterpillars of the spruce moth ( Grapliolitha pactolana), 
or by hail. The mycelium lives chiefly in the bark and bast ; 
during the active growtli of these tissues further extension of 
the mycelium is almost completely hindered by the formation 
of a secondary cork, but in the resting periods of these tissues 
of the host, new hyphae are rapidly produced. Reproduction 
is brought about by little unicellular, and larger multicellular 
sickle-shaped conidia produced on conidiophores. The mycelium 
frequently proceeds as soon as formed to give off the smaller 
variety of conidia. The dark-red perithecia are produced later 
on the same stromata as the conidia. The asci contain eight 
bicellular spores ; the paraphyses are very delicate and slightly 
branched. 

The fungus sometimes occurs epidemic in spruce plantations, 
and may be the cause of many deaths. According to Magnus, 
the larch and eembran pine may also be attacked. As a pre- 
ventive measure all dead parts should be cut out and burned. 

Nectria Rousseliana Tul. lives in and kills leaves of the 
box ( Blum ). 

Nectria pandani Tub 3 is said to be the cause of a disease 
on Pcuulanus, also ascribed to Mclanconium pandani. The 
Pandanus disease has been reported from the Botanic Gardens 

1 Young forests in districts subject to hailstorm, ( eu ;/. on the lower Alps 
of Bavaria), may become completely infested with Nectria through hail-wounds. 
(Edit.) 

-’ll. Hartig, Untersuch. an* d. for* I -hot an., In*titnt. I., 1S8S. 

‘Schroeter (“Ueber die Stammfaule d. Pandaneae," Cohn's lit it r. Bio/, it. 
J’flanvn. Bd. I., 1895) suggests that this Mdanconium is a conidial form of 
Xectria. During the investigation of a case of a Panda mis killed in the Palm 
House at Edinburgh Botanic Garden, J. H. Burrage found both forms present 
and agreeing in order of development with Schroeters observations. (Edit.) 


NECTRIA. 


189 


of Breslau, Berlin, Paris, Kew, Glasnevin (Dublin), and 
Edinburgh. 

Nectria ipomoeae Hals . 1 Stem- rot of egg-plant and sweet 
potato. In America this attacks young growing plants, and 
causes stem-rot. The Fusarium- stage developes as a white 
mouldy coating on the withered stem, and is followed later 
by flesh-coloured clusters of perithecia. 

Polystigma. 

On the leaves of species of Frames, one finds bright-coloured 
spots, these are the stromata of this family, and in them 
are embedded pycnidia containing hook- 
shaped conidia. Perithecia embedded 
in a similar manner are developed 
after the fall of the leaves, they contain 
asci with eight unicellular elliptical 
spores, which are expelled on reaching 
maturity in spring. 

Polystigma rubrum (Pers.) (Britain 
and U.S. America). This appears as red 
circular spots on the leaves of plum and 
sloe. Micropycnidia are developed in 
summer on the under-surface of the leaf 
and give rise to curved conidia. The 
perithecia begin their development in 
summer, but only reacli maturity in the 
following spring, after the leaves have 
fallen from the tree and lain on the 
ground over winter. The asci are club- 
shaped, long-stalked, and contain eight p^tingredspotecontefnpe^ 

spores, which are set free in succession Sown patehefoTpucdnA pruni 
from April to June. Germination ensues “f th 1 eieS° w ^. 0 Tube«f : dei.V mrt 

on young leaves, and in six weeks 

pycnidia reappear. A variety, “Amyydali Desm.,” is found on 
the leaves of the almond ( Amyydalus communis). 

Frank and Fisch found in connection with P. rubrum, 
certain hyphae which they designate as trichogynes, while 

they regard the small form of conidia as spermatia which 

description and illustrations in N. Jersey Agric. Exper. Station Report, 1891. 



190 


ASCOMYCETES. 


fertilise the trichogyne and cause it to develop as an 
ascogonium. 

P. ochraceum (Wahlenb.) (P. fulvum D. C.) causes yellowish- 
red spots on leaves of Primus Pad us. 

P. obscurum Juel. produces thickened leaf-spots on Astra/jalus 
(dpinus and A. oroboides\ on the under side these are whitish, 
on the upper side they show the spermogonia as red points. 

The damage caused by Polystigma is easily kept in check 
by burning infected leaves in autumn. 


Epichloe. 

The stromata form on the stems of grasses yellowish mould- 
like coatings in which the flask-shaped perithecia are embedded. 



Fig. 83. — Epichloe typhina, forming Humorous white cushions, which completely 
encircle the gniH8*stoms. (v. Tubcuf phot.) 


The asci are cylindrical, and contain eight thread-like unicellular 


EPICHLOK 


191 


spores. The formation of perithecia is preceded on the same 
stroma by that of conidia . 1 

Epichloe typhina Tul. 'Britain and U.S. America). This 
may be found on many grasses as a mouldy coating which 
surrounds the haulms and causes withering of the parts above 
it. The fungus not unfrequently attacks such fodder-grasses as 
Dactylis, Poa, and Phleum praetense, causing severe loss where these 
crops are much grown. On the white stromata conidiophores are 
produced, and from them small, ovate, unicellular conidia are 
abjointed. These are followed later by perithecia embedded in 
the same stromata. The asci, of a somewhat yellowish colour, 
are long with button-shaped apices and contain eight thread- 
like spores. 

Ep. Warburgiana, Magn. 2 is an interesting species found on arrowroot 
(Maranta) in the Philippines. 


Claviceps. 

The sclerotia are black horn-like bodies, and on them the 
stromata are developed as stalked structures, with spherical 
heads, in which the flask-shaped perithecia are embedded. The 
asci contain eight thread-like spores. 

Claviceps purpurea (Fries 3 ) (Britain and U.S. America). 
This fungus becomes most apparent, when in the stage of 
the well-known “Ergot” grains, bluish-black curved sclerotial 
bodies in which the mycelium perennates over winter. Ergot 
is found in the ears of our cereals, especially in rye, also in 
other cultivated and wild Gramineae. The sclerotia fall into 
the ground direct, or are sown out with the seed, and in 
spring or early summer produce a large number of stromata, 
each consisting of a violet stalklet carrying a reddish-yellow 
head. The ovoid perithecia are completely buried in the head 
of the stroma, and contain the asci, each with eight thread-like 
ascospores. The spoi’es, after ejaculation, germinate on flowers 
of Gramineae, and the septate mycelium developes in the outer 

1 Atkinson, G. F. ( Torrey Club Bulletin, 1894, p. 222), proposes a revision 
of the species of Epichloe and other species of N. American graminoeolous 
Hypocreaceae. (Edit.) 

-Magnus, Inter nat. Bot. Congress, 1892. 

,! Tulasne, Anna/, cl. sci. natur. 3 ser. xx. Kuhn, Mittheilungen cl. land- 
mirth. Institut. Halle, 1863. 


192 


ASCOMYC ETKS. 


coats of the ovary, till gradually but completely it fills up the 
whole cavity. Outside the ovary the mycelium forms an 



Fio. 84. — Clavieept purpurea. Ergot. Sdorotia or Ergot -grains in cars of Rye. 
(v. Tubeuf phot.) 


irregular wrinkled white stroma or sphacelia, from the hollows 
and folds of which little ovoid conidia are abjointed from short 


CLAVICEPS. 


193 


conidiophores. A very sweet fluid, the so-called “honey-dew,” 
is separated from the sphacelia ; this attracts insects, which 
carry the conidia to other dowers. Since the conidia are 
capable of immediate germination, and give rise to a 
mycelium which penetrates through the outer coat of the 
ovary, the disease can be quickly disseminated during the 
flowering season of the grasses. After the formation of conidia 
has ceased, the sclerotia become firmer, with a dark wrinkled 
cortical layer and an internal firm-walled pseudoparenchymatous 



Fig. So . — Claviceps purpurea. A, Selerotium with seven stromata (cl). IS, 
median longitudinal section through the upper part of a stroma, the flask-shaped 
perithecia (c//) are embedded in the head. C, Perithecium in longitudinal section 
(highly magnified) — hy , hyphal tissue ; sh, cortical tissue of the stroma ; cp, orifice 
of the perithecium. D, Isolated ascus ruptured, so that the thread-like asco- 
spores Op) have begun to escape. (After Tulasne, from Sach s Lehrbuch.) 


hyphal tissue. In this condition they are introduced along with 
grain into bread, which when eaten acts as a powerful poison, 
producing very serious results (Ergotism). The sclerotia are 
also used medicinally, and are collected for this purpose ( Secede 
cornutum). 

Robert (Frohner, Lehrbuch der Toxikologie fiir Thierdrtze , 1890) states 
that Ergot contains three poisonous agents : 

(1) Cornutin, an alkaloid which produces that particular effect of ergot 
in causing contraction of the uterus. 

(2) Sphacelic acid, a non-nitrogenous, resinous, non-crystallizable sub- 
stance, insoluble in water and dilute acids, but soluble in alcohol, and 

N 


194 


ASCOMYCETES. 


forming, with alkalies, salts soluble in water. This is the real cause of 
ergot poisoning and gives rise to gangrene. In large doses it produces 
cramp similar to strychnine, and tetanus of the uterus. 

(3) Ergotic acid, a nitrogenous, easily decomposed glycoside, which has 
no effect on the uterus. It is more a narcotic which diminishes reflex 
excitability and finally stops it. 

Robert experimented chiefly with cattle and fowls. He found that an 
acute course of the poisoning can be distinguished from a chronic ; also a 
gangrenous ergotism from a spasmodic. The symptoms of the disease are : 

(1) Gastro-enteric, an excessive salivation accompanied with redness, 
blistering, inflammation, wasting and gangrenization of the mouth-epithelium; 
similar changes also occur on the epithelium of the gut, producing vomiting, 
colic, and diarrhoea. 



Flo 86. — Sclerotia of Clavier p» mirroccphaln 
on Molinia cocrvlta. (v. Tubeuf phot.) 


(2) Gangrenization and mummifica- 
tion of extremities, consisting of a 
drying-up, a dying-off, and a detach- 
ment of extremities, such as nails, 
ears, tail, wings, claws, toes, and point 
of tongue. 

(3) Spasmodic contraction of the 
uterus and consequent abortion. 

(4) Nervous phenomena such as in- 
sensibility, blindness, paralysis, etc. 
The presence of, ergot may Vie de- 
tected both microscopically and spec- 
troscopically. 

The fungus may be combated 
by careful separation and de- 
struction of sclerotia, and by the 
use of clean seed . 1 

Claviceps microcephala 
(Wallr.) (Britain). This is found 
on P/rrrtrjmites, Molinia, Man/ns, 
etc. It has smaller sclerotia, 
which, according to Hartwich,- 
contain three times as much 
Ergotin as those of Cl. purpurea. 


1 Smith (Disrates of field and garden crops. 1SS4. p. 233) describes and 
figures C/ariceps purpurea car. Wilsoiii on (Hyceria fi nil aim near Aberdeen, ll 
is distinguished “ in being whitish or yellowish, instead of being pale purple in 
colour, and in the perithecia or conceptacles being almost free on an elongated 
club-like growth instead of being immersed in a globular head or stroma." 

*Hartwich, “Selerote du Molinia coerulea." II id It I . dc la Sor. Mycolotj. d t 
France. 1SU5. 


CLAVICEPS. 


195 


Cl. nigricans (Tul.) on Hdeochciris and Scirpus, with sclerotia 
of a dark violet colour (Britain). 

Cl. setuloso (Quel.) on Poa. Stromata straw-yellow in colour. 

Cl. pusilla Ces. on Andropogon Ischaemum. 


(2) SPHAEKIACEAE. 

The group of the Sphaeriaceae includes eighteen families, 
but only the following contain parasites of interest to us. 

Families : Trichosphaerieae, Melanomeae, Amphispliacrieae, 

Cucurbit avicae, Sphaerelloidcac, Pleosporeae, G-nomonieae, Vcdseae, 
Diatrypeae, and Melanconideae. 

TRICHOSPHAERIEAE 

(including Coleroa and Herpotrichia). 

Coleroa. 

The perithecia have thin walls with radiating bristles, and 
sit superficially on the substratum. The asci have thickened 
apices, and contain eight two-celled, faintly coloured spores. 

Coleroa chaetomium Kunze, occurs on living leaves of 
Rubus caesius and R. Idaeas. In addition to perithecia, it 
forms conidia known as Exosporium rubi Xees. 

C. alchemillae Grev. (Britain and U.S. America). On leaves 
of Alchemilla vulgaris. 

C. andromedae Behm. On leaves of Andromeda polifolia. 

C. potentillae Fries (Britain and U.S. America). Leaves of 
Potentilla anserina. It forms perithecia which are situated 
on the leaf-ribs ; also conidia ( Marsonia potentillae). 

C. subtilis Fuck. On leaves of Potentilla cinerea. 

C. circinans Fries. On leaves of Geranium rotundifolium and 
G. molle. 

C. petasitidis Fuck. On leaves of Petasites officinalis. 

Trichosphaeria. 

Perithecia small, spherical or ovoid, and more or less hairy. 
Paraphyses distinct. Spores with one, two, or four cells. 

We give this genus a wider scope than Winter, and include species with 
one, two, and four-celled spores of hyaline or light colour, and whose 


196 


ASCOMYCETES. 


other characters coincide ; this seems to be all the more justifiable since 
one finds on the same species asci with spores made up of one, two, or 
four cells. 

Trichosphaeria parasitica Hartig. 1 (Britain and U.S. 
America.) Everywhere in young naturally regenerated woods 
of silver fir, especially in damp places or where the plants 
are crowded, one finds partially browned needles hanging 
loosely from the twigs, held only by a fine white mycelium 
(big. 87). In addition to this, one finds in spring young 
twigs completely enveloped in mycelium, with all their 



Fig. S7.— Trichotphncria paralitica on Silver Fir. The withered and dead 
needles hang loosely downwards, attached to the twig only by a white mycelium, 
(v. Tubeuf phot.) 


needles killed, so that the twig itself soon dies. The white 
mycelium grows especially on the under side of the shoot, 

and on the lower epidermis of the horizontal needles. A 

pseudoparenchyma, consisting of layers of mycelium, is there 
laid down, the lowest layer of liyphae sending short cone- 
shaped haustoria into the walls of the epidermal cells (Fig. 88). 
Inside the needles, occupying the intercellular spaces, there 
are numerous branches of septate liyphae, which kill the cells 
of the leaf. The perithecia occur here and there on the 

mycelial coating outside the leaf ; they are spherical and 

blackish, with radiating hairs. They contain paraphyses and 

1 R. Hartig, “ Ein neuer Parasit d. Weisstanno.” Alley. Foist, -u. Jagd- 
Zcitung , .Jan., 1SS4. 


TRICHOSPHAERIA. 


197 


asci, the latter with eight four-celled light-grey spores, which 
germinate directly and distribute the fungus over new host- 
plants. 

I found this same fungus on Tsuga canadensis 1 at Baden- 
Baden, and on spruces in several parts of the Bavarian forests . 2 
It, however, rarely attacks spruces, although they often occur 
in the same forest with firs. One of the cases of infection 
referred to above was caused by the diseased branch of a fir 
lying in contact with a twig of the spruce, so that the mycelium 
grew from the one to the other ; the spruce needles were killed, 
and woven on to the twig by hyphae. 


Fig. 88. — Trichosphaeria i parasitica.. Mycelial cushion on lower side of Fir 
needle, a, Filamentous mycelium, which, at b, sends downwards numerous 
branches to produce a cushion of parallel hyphae, c. Where the mycelium rests 
on the epidermis, rod-like haustoria are sunk into the outer wall of the epidermal 
cells, e e ; d shows the mycelial cushion slightly detached from the epidermis, so 
that the haustoria have been withdrawn. //, Epidermal cells filled with brown 
contents, g g , Chlorophyllous mesophyil, which becomes brown after the 
mycelium has penetrated to it. i, Outer court of a stoma filled by a mycelium 
with no haustoria, but adhering to the waxy granules of the stomatai aperture. 
(After R. Hartig.) 



In woods of young silver fir naturally regenerated, this fungus 
causes great damage by killing numerous twigs. It occurs every- 
where in young fir forests, e.g. the Alps, Bavarian forests, the 
Black Forest, etc. On dry airy situations, on free-standing 
trees, and on the highest branches of a tree, it is rarely present. 

1 v. Tubeuf, Beitrdge z. Kenntn. d. BaumkranJcheiten, Berlin (Springer), 1888. 

2 v. Tubeuf, “ Trichosphaeria parasitica der Fichte.” Bolan. Centralblatt , 
xli. , 1890. 


198 


ASCOMYCETES. 


Its injurious effects can be minimized by removal of attacked 
branches. 

Trichosphaeria sacchari Massee, is regarded as a dangerous wound 
parasite of cane-sugar in the Antilles ; it seems to obtain entrance chiefly 
by the canals left by a caterpillar. 1 


Herpotrichia. 

The smooth dark perithecia bear long brown hairs, which 
do not stand erect and stiff, but are more or less prostrate. 



Fio. SO.—Hrrpotriehia nigra on a branch of Piniu monlana. The ends of the 
twigs, with most of the younger needles, are still green ; the others are dead and 
felted together by hyphae into a black mass. (v. Tubouf phot) 

The asci contain eight spores, at first generally two-celled, later 
becoming four-celled. 

'Massee G., Anna/* of liotany, 1893, p. 51i>. 

Rarbcr, “ Experimental Cultivation in St. Kitto," Lcticard Island s Gazette, 
1894. 


HERPOTRICHIA. 


199 


Herpotrichia nigra Hartig. 1 This parasite is distinguished 
by its grey mycelium, which covers and completely envelops 
twigs and young plants. On the dwarf mountain pine it is 
not uncommon to find branches bearing patches of blackened 
needles closely bound together by gossamer threads, the other 
parts remaining still green and forming a background against 
which the blackened masses show up prominently (Fig. 89). 
Young spruce plants under a metre in height and the lower 
branches of taller trees are frequently completely enveloped in 
mycelium, and, where they have been pressed down to the 
ground by weight of snow, the twigs may be woven round 
and fastened to the earth by a felt of mycelium. 



Fig. 90 . — Herpotrichia nigra, a, hyphae weav- 
ing a granular mycelium on the surface of the 
needle and forming tuber-like bodies over the 
stomata ; rod-like haustoria are sunk into the 
outer walls of the epidermal cells. (After R. 
Hartig). 


Fig. 91. — Herpotrichia nigra. Ascus with 
germinating spores, (v. Tubeuf del.) 


I have frequently observed the fungus on Juniperus com- 
munis, especially in Bavarian forest-land, and on Juniperus 
nana in the Alps. Professor Peter found it on the latter 
host in Sweden. 

The spherical dark-coloured perithecia are covered with 
prostrate hairs, and contain asci with eight four-celled spores. 
The spores germinate directly to hyphae. The mycelium closely 

1 R. Hartig, “ Herpotrichia nigra.” Alleg. Forst.-u. Jagd-Zeitung, 188S. 
v. Tubeuf, “Mittheilung iib. einige Feinde d. Waldes.” Alleg. Forst.-u. 
Jagd-Ztitung, 1887. 


200 


ASCOMYCETES. 


envelops the needles and sends out haustoria similar to 
Trichosphaeria parasitica (Fig. 90). 

Herpotrichia is, in high-lying situations, a very dangerous 
enemy of young spruces, and nurseries in such places have 
frequently to be abandoned owing to the death of all the 
plants. Serious damage also frequently results in young planta- 
tions where snow lies long and keeps the young trees pressed 
down towards the earth. Then the fungus, even under the 
snow-covering, weaves round and fixes the shoots so firmly 
together, that only the healthy ones are able to free themselves 
again and to resume their growth in spring. 

As preventive measures, nurseries should not be established 
in high situations, nor in valleys where there is a large snow- 
fall ; while in localities liable to attack, the planting of young 
trees in basins or cups (hole-planting) should be avoided. The 
loss from crushing-down by snow may be lessened by laying 
trunks and branches of felled trees amongst the young plants, 
and by going over them in spring, raising up all prostrated 
plants. 


MELANOMEAE. 

Rosellinia. 

The perithecia generally occur in numbers together; they 
are black, and smooth or studded with bristles. The asci 
contain eight oval, spindle-shaped, dark-coloured, one-celled 
spores. Filamentous paraphyses are always present. 

Rosellinia quercina Hartig. 1 The oak-root fungus. This 
fungus lives in the roots of oak seedlings one to three years 
old, and causes the leaves and shoots to become pale and to 
dry up. It spreads only during damp weather, especially 
in June, July, and August. In wet years it may cause very 
serious damage, especially in seed-beds. The mycelium pene- 
trates into the living cells of the root-cortex, extending even 
to the pith. At first the mycelium is hyaline, but later it 
darkens, and the hyphae become twisted together into spun 
thread-like strands — the rliizoctonia. These, structures apply 
themselves to roots of neighbouring plants, and soon enclose 
them in a weft of hyphae ; by this means the disease is 

1 R. Hartig, Unlersuch. aits d. farstltotan. Inslitut zu Milnchen, Berlin, 1SSS. 


ROSELLINIA. 


201 


propagated through the soil from plant to plant. There is a 
resting-stage in the form of chambered sclerotia, black tuber- 
like bodies which have their origin in the cortical parenchyma 
of the roots and break out through the cortex. Reproduction 
is effected throughout the summer by means of conidia, pro- 
duced from a mycelium which vegetates on the surface of the 
soil ; this mycelium bears conidiophores with whorled branches, 
from which the conidia are abjointed. 

The perithecia are spherical structures composed of hyphae 
with walls which swell up in a gelatinous manner. At first 
the inside of the perithecium is a gelatinous mass containing 
the paraphyses and the rudiment of the ascogonium. As the 
asci are developed, they push their way into the gelatinous 
mass amongst the paraphyses. Each ascus is a long club- 
shaped tube, the apex of which is thickened and stains blue 
with iodine, showing at the same time a canal piercing it. 
The ascospores are canoe-shaped with sharp ends, and when 
mature have a dark brown colour. The spores germinate in 
spring ; in water-cultures germ-tubes are emitted twenty-four 
hours after sowing. The spores open by a longitudinal slit, and 
a germ-tube emerging from each end branches into a mycelium 
which soon takes on the form of a rhizoctonia-strand. Infection 
takes place through the tender non-cuticularized apices of roots. 

The fungus may be combated if diseased portions of seed- 
beds are isolated by means of trenches dug round them. If 
boards soaked in carbolic acid or coal-tar are placed upright 
in the trenches, greater certainty will be secured that the 
disease does not spread. 

Several species of Mhisoctonia, probably related to the above, 
may now be briefly considered. 

Rhizoctonia violacea Tub 1 (U.S. America). Root-fungus of 
lucerne and clover. The presence of this disease is shown in 
summer by the plants withering, and finally dying. The mycelium 
lives inside the roots, and covers them externally with violet 
coatings on which the sclerotia appear as black tubers. 

On plants with sclerotia, Fuckel found pycnidia and perithecia of 
Leptosphaeria (Trematosphaeria or Byssothecium) circinans ; whether the 
various forms were related could not, however, be determined. 

1 Rostrup, Undersuegelser angaaende Svampeslaegten Rhizoctonia, 1886. 

Tulasne, fungi hypogaei, PI. IX. and XX., 1851. 


202 


ASCOMYCETES. 


The disease spreads through fields in a centrifugal direction 
from a starting-point. Besides the above plants, it is also 
said by Kuhn to attack carrots, sugar-beet and mangolds, 
fennel and potatoes ; and Tulasne gives asparagus and red 
clover as hosts. Brunet 1 believes that the fungus remains 
three years in the soil, and recommends that diseased fields 
should not be cropped with lucerne or clover for several years. 
He also advises the isolation of infected land by surrounding 
it with a deep trench in which sulphur is strewn, then covered 
over with soil. The enclosed plot should next be deeply 
trenched between June and August, and all plant-remains 
removed and burnt. 

Rh. crocorum D. C . 2 3 The Saffron destroyer. This parasite 
attacks and kills conns of the saffron ( Crocus sativus). The 
mycelium finds entrance by the stomata of healthy conns, 
and covers them externally with a web of violet-coloured 
mycelium. 

Rh. solani Kuhn, occurs as black sclerotia on the skin of 
potato-tubers. 

Rh. batatas Fr. occurs in America on sweet potato. 

Rh. allii Grev. occurs on tubers of shalot ( Allium ascalonicum) 
and onion (A. sativum). 

Rh. betae Kuhn is said to attack beet-root in America . 8 

We may also consider at this place : 

Dematophora necatrix Hartig . 4 5 The vine-root fungus. 
This parasite causes a very destructive disease of the vine, 
and is often confused with attacks of the Phylloxera-insect. 
It occurs in the United States, and is common throughout 
France, Switzerland, Italy, and South-west Germany, being 
known under a variety of names . 6 * Occasionally it has been 
known to attack the roots of fruit trees and other plants 
cultivated in vineyards. 

1 Prunet, “ Sur le Rhizoctone de la Luzerne.” Compt. rend., Paris, 1893. 

Fr. Wagner, “ Das Vorkommen des Wurzeltoters d. Luzerne.” Zritsch. d. 
Landwirth. Verein in Bayern, IS94. 

2 Prillieux, “Sur la mal&die des Safrans.” Compt. rani., xciv. and xcv. 

Tulasne, Fungi hypogaei, PI. VIII., 1851. 

3 Iowa Agric. Exper. Station, Bulletin 15, 1891 ; with illustrations. 

4 R. Hartig, Untersuchungen aus d. forstbotan. I nst it tit sii Miinchen, in., 1 883. 

5 Wurzelpilz, Weinstockfaule, Pourridit 1 de la Yigne, Pourriture, Blanc des 

Racines, Blan<|uet, Champignon blanc, Aubernage, Mai nero, Morbe bianco, etc. 

(Hartig's Lehrbwh). 


DEMATOPHORA. 


203 



Fig. 02. — Vine-stock with Dematophora necatrix 
(after a prolonged stay in a moist chamber), a, Fila- 
mentous mycelium passing over into rhizoctonia- 
strands (b), which anastomose at c c. d and e, 
Rhizomorphs growing outwards from the interior. 
(After R. Hartig.) 



Fig. 93. — Vine-root with rows of black 
sclerotia exposed, and bearing bristle-like 
conidiophores here and there. (After R. 
Hartig. ) 



Fig. 04.— Portion of Fig. 93 after for- 
mation of conidiophores. x (After 
R. Hartig.) 


204 


ASCOMYCETES. 


Dematophora forms fine rhizoctonia-strands which grow 
through the soil from root to root. The mycelium kills the 
fibrous rootlets, and spreads from these into older roots to 
form rhizomorph-strands, which, however, have a structure 
quite distinct from those of Agaricus melleus. The rhizomorph- 
strands may pass out of the root into the soil, there to form 
a filamentous mycelium, or, remaining in the root-cortex, may 
produce rows of black tuberous sclerotia which on maturity 
break out to the exterior. On the sclerotia, or other parts 
of the mycelium, bristle-like conidiophores may be developed 
as branched panicles from which ovoid colourless conidia are 
abjointed. 

This enemy of the vine is rapidly assuming great import- 
ance. Thus, for instance, in Baden , 1 there is no Phylloxera, 
but whole tracts of vine land are infested with Dematophora. 

According to Yiala , 2 Dematophora forms perithecia, which, 
however, only develop after artificial culture for several years 
on decayed plants. If this be so, the fungus should be classi- 
fied between the Tuberaceae and the Elaphomycetes. Berlese,* 
however, contests this view, and regards it as nearly related 
to Jiosellinia. 

Ilartig 4 suggests impregnation of the vine poles with creosote 
as a means of combating this disease. 


Strickeria. 

Strickeria Kochii Korb. develops its perithecia on the cortex of living 
Itobinia Pseudacacia ; its parasitism is however not yet fully established. 

CUCURBITARIEAE 

Gibbera. 

The black perithecia, beset with stiff bristles, are developed 
in large groups on a dark pseudoparenchymatous stroma. 

Gibbera vaccinii Sow. (Britain). In damp situations amongst 
moist patches of Hgpuuvi and other mosses, one often finds 
the cowberry ( Vaccinivm Vitis-hlaca) with its leaves and 

1 Beinling, Da* Aujlreten v. Pebenkrankheiten in Baden, 1801. 

2 Viala, Monographie du Pourridie d. Vignes, 1801. 

3 Berlese, Piri.il a di patotogia vegetate, I. 

* R. Hurtig, Lehrbuch <!. Baumkrankheittn, English edition, 1804, p. ST- 


GIBBERA. 


205 


twigs brown and dead (Fig. 95). If more closely examined, 
the twigs will be found to bear patches of coal-black, 



Fig. 96. — Gibbera vaccinii. Isolated ascus 
with eight spores ; isolated hair from the 
outside of a perithecium. (v. Tubeuf del.) 


Fig. 95 . — Gibbera vaccinii on 

Cowberry. The perithecia form 
black patches on the living leafy 
branch, as well as the dead brown 
one. (v. Tubeuf del.) 


Fig. 97. — Gibbera vaccinii. Cross-section of Cowberry showing 
a patch of perithecia in section ; the hairy perithecia contain 
paraphyses and asci with spores ; a mycelium permeates the 
cortical tissue of the host. Short hooked hairs cover the 
epidermis of the stem. (v. Tubeuf del.) 


spherical perithecia, which are coated by short, acute, unicellular, 
black hairs (Fig. 97). The perithecia contain paraphyses and 


206 


ASCOMYCETES. 


asci, the latter with eight or fewer bicellular dark-coloured 
spores. The mycelium is dark-coloured, very vigorous, and 
furnished with many lateral bladder-like outgrowths ; it permeates 
the whole cortical tissue as far in as the wood, and under the 
epidermis forms a brown pseudoparenchymatous stroma, which 
extends over the cortex, and gives rise to numerous perithecia. 
The living cells of the cortex turn brown in presence of the 
fungus-mycelium, and collapse, causing the whole shoot above 
the place of attack to wither and die. 

Cucurbitaria. 

The dark perithecia and pycnidia break through the epidermis 
in large numbers. The asci contain six to eight brown spores, 
divided by cross-septa. 

Cucurbitaria laburni Pers. 1 (Britain). The spores of this 
fungus germinate on wounded parts of laburnum ( Cytisus 
Laburnum), and, as the branches of attacked plants soon die 
off, considerable damage to nursery stock may result. The 
mycelium spreads through the wood, particularly the vessels, 
in spite of the early stoppage of these by a yellow wood -gum. 
Diseased parts of the wood of living branches appear as dark 
strips ; reproductive organs are produced in the bark, and 
there the plant attempts to isolate the diseased parts by con- 
tinued cork formation. 

If diseased, but still living spots on stems be examined, 
they will be found to include many yellow and black pustule- 
like swellings, some buried in the bark under a periderm eight 
to ten cells in thickness, others in process of breaking through 
or altogether exposed. Many of the pustules will attract 
attention from the presence of red, twisted, elongated tendrils 
on them. On the lower parts of dead branches the same 
appearances will he found, but, in addition, the periderm will 
generally be ruptured, and the openings so produced tilled with 
spherical dark grey or black fructifications. These are variable 
in form, and amongst them can be distinguished some which 
are very large, round, smooth-coated, and light-coloured, with 
a round pore ; others, which appear more warty, and have a 
depressed opening; while still others, generally smaller, have 


1 v. Tubeuf, “Cucurbitaria laburni.’' Rolan. Ctnlra/Malt, xxvi., lSS(i. 


CUCUKBITARIA. 


207 


an acute beaked pore. Where the bark has been lost, a 
good lens may distinguish the spherical or ovoid dark-coloured 
perithecia. On the finer twigs the whole 
bark is often perforated by numerous tiny 
pycnidia, hardly distinguishable with the 
naked eye. 

If these various forms of fructification be 
submitted to microscopic examination, sections 
through the yellow pustules will show them 
to have that colour, because the transparent 
periderm has become loosened from the rest 
of the bark ; underneath the corky layers 
will be found a red stroma of pseudo- 
parenchymatous hyphal tissue. This stroma 
by its growth causes a gradual rupture and 
loosening of the corky and other layers of the 
periderm ; wherever this takes place, conidio- 
phores are developed, and give off numbers of 
tiny, hyaline, ovoid or cylindrical conidia. 

The stroma itself is somewhat spongy, and 
encloses numerous cavities which also become 
lined with conidiophores. At a later period 
the tissue enclosing these cavities may become 
dark coloured, so that structures similar to 
pycnidia are formed. In such cavities the 
red colour disappears, and the hyphae, coni- 
diophores, and conidia appear transparent. 

The real pycnidia appear later, and consist of 
a peridium of coarse pseudoparenchyma con- 
taining conidia similar to those just described Fig . 9 s ,—cucurutaria 
(Fig. 99, A). From the openings of these bumum (diagrammatic 
pycnidia the conidia emerge as red tendrils, stm 'living, 6 and werej'n 
rising as much as one centimetre above the precedlnlsummer^ 
pore. Adjoining these forms of sporophore rind \ pl S W and the 
just described will be found others : unde- «°an’d y 6 er thl iP nerithecia 
veloped perithecia with young asci ; dark- a a £ 
brown pycnidia with brownish-grey, multi- 
septate, compound conidia ; or similar pycnidia 
with unicellular spherical, brownish -grey conidia. 

Where the disease has made further progress, the pustules 



extended into the wood. 
(After v. Tubeuf.) 


208 


ASCOMY C'ET ES. 


will be found changing from yellow to black on account of 
the periderm and dead stroma becoming darker. On dead 
branches the large cushions of fructifications will be found to 
include : (a) perithecia with a warty exterior and pores set 
in a depression ; ( b ) large pycnidia, standing out from the 
cushions, with brown smooth coats, and full of compound 
multiseptate conidia (Fig. 99, B ; see below Xo. 3, a); (c) 
other smaller pycnidia containing the same conidia, but whose 
pore is situated on a sharp prominence (Xo. 3, b). All or any 
of the three forms may be present. 




Fkj. 90. — Cucurbitaria laburni. A, Stroma with pycnidia containing minute 
unicellular conidia. B, One of the large smooth pycnidia. (After v. Tubeuf.) 


The mature perithecia have a peridium consisting of a loose 
pseudoparenchyma with a rough warty exterior and a pore set 
in a distinct depression (Fig. 100.) The paraphyses are long, 
strong threads, often branched, and between them arise the 
long cylindrical asci with rounded ends. The normal number 
of ascospores is eight in each ascus, but fewer is no exception. 

In addition to the forms already described, pycnidia of still 
another sort occur (No. 1, c). They are spherical, with a 
dark-coloured coarse peridium, and are smaller than the stroma- 
pycnidia. These pycnidia contain no conidiophores, but give off 


CUCURBITARIA. 


209 


unicellular conidia, at first white, later grey. It is these pyenidia 
which cause the fine perforations of the periderm of twigs. 

Yet another form of pyenidia, previously known as Diploclia 
cytisi (Awd.), (No. 4). This, like the last, breaks through the 
corky layers of the bark. It has a peridium composed of loose 
pseudoparenchyma and, without the intervention of conidio- 
phores, produces two- celled conidia of a dark greyish-brown 


A 



Fig. 100. — Cucurbitaria labumi. Perithecium isolated. A, Ejaculating ascus 
■with the inner membrane as yet unruptured, but emerging beyond the outer 
ruptured coat. (After v. Tubeuf.) 

colour. This form, however, I failed to find in the course of 
my investigation, although I looked through much material. 
Tabulating these various forms of fructification we have : 

A. Pycnidia. 

1. White transparent, small, unicellular conidia on long conidiophores : 

(a) Free on the stroma. 

( b ) Enclosed in cavities in the stroma : 

(a) In cavities as yet not resembling pycnidia. 

(/?) In cavities with firm dark-coloured periphery. 

(c) Enclosed in dark-coloured free pycnidia, with a peridium of coarse 

pseudoparenchyma. 

2. Brown, unicellular, round conidia, in little brown pycnidia (Fig. 99, a). 

O 


210 


ASCOM V CETES. 


3. Brown, multiseptate conidia : 

(a) In brown, very large, smooth-coated pycnidia (Fig. 99, b). 

( b ) In darker and smaller pycnidia with pointed aperture. 

4. Brown, bicellular conidia, in little dark pycnidia ( Diplodia cytisi). 

B. Pkrithecia. 

5. Brown, multiseptate ascospores, in perithecia generally of dark colour, 
and with depressed pore (Fig. 100). 

Cucurbitaria sorbi Karsten. This fungus appears to pro- 
duce disease in a manner similar to C. laburni. It was described 
by me in 1886 1 from specimens collected in the Bavarian 
forest-land from young Pyrus Aucuparia. They were easily 
distinguished in August by their withered twigs, both bark and 
wood being killed in tracts by the mycelium. In another 
locality I found well-developed perithecia, also on P. Aucuparia. 

Cucurbitaria pityophila Fries, occurs on the living branches 
of various conifers, e.g. Pinus Cembra. 

SPHAERELLOIDEAE 

Stigmatea. 

The naked perithecia are superficially seated on the sub- 
stratum. The ascospores, eight in each ascus, are clear and two- 
celled. The species are parasites. 

Stigmatea robertiani Fr. (Britain and U.S. America). Occurs 
on living leaves of Geranium Robert ian um. 

St. ranunculi Fries. On living leaves of Ranunculus repens 
(Britain and U.S. America). 

St. mespili Sor. (U.S. America). This species appears in 
spring as reddish-brown spots on the leaves of wild pear-trees. 
At these places the epidermis becomes ruptured, and cushions 
are formed from which brown conidia are given off from short 
conidiophores. This stage was formerly known as Morthiera 
mespili. The conidia are at first obovoid, but later seem to 
consist of four separate cells arranged in a cross, and each 
furnished with a transparent bristle. Each conidium produces 
a germ-tube which penetrates the epidermis, and in a month 

1 1 have since found from Saccardo that this fungus was described by Karsten 
(I fi/col . Feint., u. “ad ramos dejectos Sorhi a unijinrim in Pennia merid. et media"); 
it was, however, unknown for Germany to that author. (Auth.) 


STIGMATEA. 


211 


new conidial cushions may appear. The mycelium itself is 
brown. From winter to spring, brown perithecia containing 
eight-spored asci may be found on the same leaves formerly 
occupied by the conidia. The colourless spores consist of two 
unequal cells ; they germinate in May, before or after ejaculation 
from the asci, and bring about new infections. 

St. polygonorum Fr. occurs on leaves of Polygonum. (Britain and U.S. 

America). 

St. andromedae Relim. On living leaves of Andromeda polifolia. 

St. alni Fuck. On living leaves of Alnus glutinosa. 

St. juniperi Desm. On living needles of Juniperus communis. 

Ascospora. 

The mycelium forms brown crusts under the host-epidermis, 
and there the perithecia develop. The asci are small and 
contain unicellular hyaline spores. The perithecia contain no 
paraphyses. 

Ascospora Beyerinckii Vuill. 1 The conidial form of this 
fungus ( Coryneum Beyerinckii) produces a form of the “ gum- 
flux ” of cherry trees. The mycelium lives in leaves of cherry, 
peach, plum, apricot, almond, which in consequence become 
spotted, and die off along with the young fruit. Mature 
perithecia may be found in spring. The fungus lives to a 
certain extent as a saprophyte. 

Sphaerella. 

The delicate perithecia are embedded in the tissues of the 
host-plant ; they contain asci with two-celled colourless spores, 
but no paraphyses are present. 

Sphaerella laricina Hartig. 2 The needle-cast fungus of 
Larch. This fungus is the cause of a dangerous larch-disease 
found everywhere, except in mountainous localities over 1200 
metres. The symptoms of disease consist in the needles becoming 
brown-spotted and falling prematurely in summer. Cushions of 
conidia are formed in June on the brown spots ; these enlarge, 
and from their surface rod-shaped; four-celled conidia are 

1 \ uillemin, Titres el travaux scientifiques , 1S90. 

2 R. Hartig, Forstlich-naturwiss. Zeitschrift, 1S95, p. 445. 

Through the kindness of Prof. Hartig we have been enabled to add an 
account of this important new disease, with the accompanying figures. (Auth. 

and Edit.) 


212 


ASCOMYCETKS. 


abjointed (Fig. 103); in the interior of the spots are produced 
tiny conidia (Leptostroma laricinum), incapable of germination. 



Fic. 101. — Tuft of larch needles, the greater number of which are more or less 
attacked by Sphaerella laricina. (After R. Hartig.) 


The rod-shaped conidia infect particularly the lower needles of 
the crown, and three weeks thereafter new conidial cushions 



Fio. 102 . — Spfuurttlo laricim i. Section through a diseased spot on a larch 
needle. The interior of the leaf is permeated with the intercellular mycelium. 

Two conidial cushions are shown ; from these numerous long rod-shaped conidia 
are given off externally (those of the upper cushion have nearly all been carried 
off by rain), while cavities inside the cushions are tilled with micro-eonldia. 

X (After R. Hartig.) 

appear. Their distribution and germination are facilitated by 
wet weather. The perithecia (Fig. 104) arc matured towards 


SPHAERELLA. 


213 


spring in the fallen needles, which lie on the ground over 
winter. The ascospores are mature and capable of infection 
at the beginning of .Tune. In forests of 
pure larch, or in mixture with spruce, the 
ascospores are easily distributed by wind. 

In larch, underplanted with beech, the spores 
are kept down towards the ground by the 
canopy of beech foliage, so that, during the 
summer, they cannot be carried up to the 
larch crown. 

Hartig gives the following interesting facts 
on its distribution. 

“ As already remarked, the perithecia de- conidia before and after 

1 • • , , , , , ,, detachment from the 

velop m spring on the fallen larch needles, basidia. b, Miero-conidia 

1 • 1 1 ,, , from the interior of the 

ancl in low-lying localities the spores reach cushions, x ±1°. (After 
maturity at the beginning of June. New R- Hartig-) 
conidial cushions are not found on the larch in our neighbourhood 
before July. The parasite has thus four months at its disposal 




Fig. 104. — Sphaerclla laricina. Section through a diseased larch needle in June 
after it has lain on the ground from the previous year. The mycelium is thick, 
thick-walled, and of a light-brown colour. The perithecia contain asci and asco- 
spores. To the extreme right is a pycnidium containing little oblong conidia, 
alongside a perithecium. x J-fa. (After R. Hartig.) 


for distribution by means of conidia. As, however, we ascend 
into the mountains, the snow lies longer, so that the perithecia 
cannot begin to form so early, the ascospores are correspondingly 
late in reaching maturity, and the season during which the 
parasite may spread is still further shortened by the earlier 
commencement of winter. At an elevation of 1500 metres, 


214 


ASCOMYCETES. 


active vegetation begins about two and a half months later than 
in the plains, i.e. at the beginning of June. The season of 
mature spores of Sphaerella is thus delayed till about the 
middle of August. On 20th September I found at this elevation 
only a few spots on the larch needles, and 
on these hardly any conidial cushions. By 
28th September this larch plantation was 
already under snow.” 

f “lt will thus be seen, that while at a 
high elevation the larch can flourish with 
a vegetative period extending only to three 
and a quarter or four months, the Sphacrdh, 
has not the time necessary for its develop- 
ment, so that the larch, though much 
handicapped, remains healthy. Similarly 
with the larch in Siberia, it grows there, 
as in the mountains, very slowly, yet this 
parasite can no longer reach it.” 

Sphaerella fragariae Tul. Strawberry 
leaf - blight. 1 In summer free conidia 
( Ramularia Tulasnei Sacc.) and pyenidia 
are produced, while the perithecia ripen in spring. 

[This destructive disease of the strawberry has been recorded 
from all parts of the United States. It first appears on the 
upper surface as small reddish spots, which rapidly enlarge, 
the centres withering and browning. The growth of the plants 
and the crop-yield is seriously impaired.] (Edit.) 

Sph. gossypina Atks. 2 [Cotton leaf-blight is a disease on 
leaves of the cotton plant caused by the Cerco/tpora -stage of this 
fungus. Small reddish spots appear on the leaf, enlarge, and 
become dry whitish spots with a red margin. The conidia 
are elongated and produced in long chains. The asci contain 
eight elliptical spores, which are slightly constricted at the 
septum when mature, one cell being usually somewhat smaller 
than the other. This disease frequently accompanies that one 
known as “yellow leaf-blight,” or mosaic disease.] (Edit.) 

1 Trelease, ITincoimn Exper. Slat ion, 1885. 

Scribner, F. L., lleport (J.S. Dtp/, of A</ricuJturc, 1SS7. Plate. Other 
papers by Arthur, Dudley, and Garman. 

2 Atkinson, Bulletin Torre;/ Boletii. Club, Vol. xvnt., IS'.M. 



Fin. 105.— Enlarged asci. 
a, immature asci without 
paraphyscs, as on April 30. 
I !>, Mature asci, from one of 
which the spores are escap- 
ing, as on June 1. x 
(After R. Hartig.) 


SPHAERELLA 


215 


Sph. mori Fuck, causes a similar disease on leaves of mulberry (U.S. 

America). 

Sph. taxi Cke. On the yew. 1 

Sph. longissima Fuck. On living leaves of Bromus asper. 

Sph. depazeaeformis (Auersw). On living leaves of Oxalis acetosella and 
Ox. corniculata. 

Sph. brassicicola (Duby.). On withering leaves of Brassicae. (Britain 
and U.S. America. 

Sph. laureolae (Desm.). On living leaves of Daphne laureola. 


Fig. 106 . — Sphaerellct fragariae on leaf of Strawberry. The section through a 
spot show's formation of conidia. (v. Tubeuf del,) 

Sph. hedericola (Desm.). On living leaves of ivy. (Britain). 
Allescher 2 describes other fungi on ivy. 

Sph. Gibelliana (Pass.). On living leaves of Citrus limonum and C. 
medica. 

Sph. polypodii (Rabh.). On living fronds of Polypodium vulgare , Aspidium 
Filix-mas, Asplenium Trichomanes, Pteris aquilina. 

Sph. vitis Fuck. On withering vine-leaves. 



1 Worth. G. Smith, Gardener’s Chronicle, xxi., 1S84. 

2 Allescher, “Blattfleckenkrankheit d. Ephues,” Zeitsch.f. Pjl.-krankheiten, 1895. 


216 


ASCOMYCETES. 


Sph. sentina (Fr.) (U.S. America). In spring of 1891 this caused at 
Cieiseuheim 1 2 a severe spot-disease on the leaves of certain varieties of pear. 
Other related species occur on pear. 

There are numerous other species of Sphaerella. Saccardo gives 279 
species, many of which are probably more or less prejudicial to plants in 
orchard or garden. None, however, are recorded as very injurious. 


Laestadia. J 

This genus is similar to Sphaerella, but has one-cellcd 
conidia ; it is distinguished from Physalospora by the absence 
of paraphyses. 

L. maculiformis (Bon.) on living leaves of various trees. 

L. (Physalospora) Bidwellii (Ellis ) 3 (Britain and l\S. 
America). The Black-rot of the Vine. This parasite attacks 
all young organs and shoots of the vine. On the leaves the 
symptoms are spots with dark sharply-defined margins, on which 
the pycnidia appear later as minute black pustules. The leaves 
die, but do not fall off, as with Sphaceloma ampclinvm. The 
berries show disease when only the size of peas, and finally fall 
off singly or in clusters. The grapes are not dusty with a 
mealy powder, nor do they burst as in attacks of Oidium 
Tuckeri. Two kinds of pycnidia occur: one sometimes described 
as spermogonia, has very small rod-like conidia, borne on thread- 
like conidiophores ; these conidia have not as yet been seen to 
germinate. The other pycnidial form ( Phoma uvicola of Berk, 
and Curt.) contains forked filamentous conidiophores, from 
which one-celled ovoid conidia (stylospores) are produced and 
soon germinate by emission of a septate hvpha. The latter 
form of conidia is produced after the spermogonia, and may be 

1 Geisenheim Jalirburh, 1892. 

2 According to the laws of priority this genus must, as shown by Magnus 
( Oesterreich . botan. Zr.il., 1S94, p. 201), be called Carlia. Bon. 

1 Bibliography : Cavarn, In/onio at dirsecanienlo dei 'jrapjxdi dtila rite, 1SS8. 

Thumen, “Die Black-rot Krankheit <1. Weintrauben.” A/leg. Weinzeitung, 
Vienna, 1891. 

Galloway anil Scribner, Report* for 1S88-S9, U.S. Dept, of Agriculture. 

Viala and Ravaz, Le* Progri* agrie. < t ritirolt. Montpelier, I888-S9. 

Rathay (1), Dcr Rlark-rot, 1891. With 19 figures (2). Re rich! Ob. tine narh 
Frankreirh z. Erforxchnng d. Blark-rol Krankheit Reisi, 1891. With 7 figures (3). 
Dtr White-rot in die Weinlaubt, 1892. 

Viala. Die Krankheiten d. Weiiatocke*. 

Linhart u. Mezey, Du Krankheiten d. Weinstorke*, 1895 (Hungarian). 

U.S. Dept, of Agriculture. Numerous references in reports and bulletins, 
where details of treatment experiments will be found. 


LAESTADIA. 


217 


found right on into autumn, even throughout the winter. 
Hibernating sclerotia are also produced, the cells of which grow 
out directly into septate conidiophores with oval conidia. 
Perithecia, externally resembling pycnidia, are formed in May 
and June on the fallen berries of the preceding year. The 
asci have gelatinous walls, which swell and burst so as to 
ejaculate their spores. Viala and Eavaz successfully infected 
living grapes by means of the larger conidia, and also by 
the germinating ascospores. 

The disease is one of the most dreaded in America. It has 
been found also in Europe, having been observed in France 
since 1885, though not as yet in Germany, Switzerland, Italy, 
or Spain. Moist situations are favourable to it. As with 
other diseases of the vine, the various varieties have different 
powers of resistance, and a judicious selection of varieties may 
prove a good preventive measure. According to Viala, the 
black-rot is found in the United States on both wild and 
cultivated vines, but never on the fruit of Vitis rupestris, V. 
Berlancieri, V. cinerea, V. Liusecomii, V. Monticola, and V. 
canclicans, and very rarely on their leaves. The “vine-stocks” 
themselves suffer little or nothing from the disease. Eathay 
says that Vitis riparici, V. rupestris, and V. Solonis, so im- 
portant as grafting-stocks, are seldom affected ; the green 
shoots of other species, however, may be attacked and the 
disease be transmitted through the graft-slip. 

For combating the disease, Galloway, Prillieux, and l’Eeluse 
recommend Bordeaux mixture. 1 

Laestadia buxi (Desm.). The perithecia of this species are 
found as tiny points on yellow spots on the lower surface of 
green leaves of box. This fungus, regarded by Desmazieres as 
saprophytic, is said by Briosi and Cavara to be parasitic. 


PLEOSPOREAE. 

Physalospora. 

The perithecia are formed under the epidermis, but are 
otherwise devoid of covering ; they contain asci and paraphyses ; 
the spores are one-celled, and ovoid or elliptical. 


'For details see Eathay ( loc . cit.), the American bulletins, etc. 


218 


ASCOMYCETES. 


Physalospora laburni ( Bonord.) occurs on living twigs of Cytisus Laburnum. 
Ph. fallaciosa Sacc. On withering leaves of Aletris and Musa in Berlin 
Botanic Garden. 


Didymosphaeria. 

Perithecia similar to Physalospora, but with two-celled spores. 

Didymosphaeria genistae Fuck, occurs on Genista pilosa. 

D. epidermidis (Fries). On living branches of Berberis, Sambucus, Salts, 
and Eucalyptus. (Britain and U.S. America). 

D albescens Niessl. On living branches of Lonicera Xylosteum and 

Myricaria yerrrtanica. 

D. dryadis (Spegazz.). On living leaves of Dryas octopetala. (U.S. 
America). 

D. populina Vuill. Prillieux and Yuillemin 1 regal’d this as a parasite, 
and the cause of a peculiar dying-off of Populus pyramidalis throughout 
Germany: Bostrup, on the other hand, ascribes this to Dothiora sphaeriodes 
Fr. Prillieux regards Xapicladium tremulae as a conidial form of Didymo- 
sphaeria ; Yuillemin, however, believes it to be saprophytic. 

Venturia. 

The perithecia are embedded in the stroma, and have stiff 
bristles round the pore ; they contain both paraphyses and 
eight-spored asci. The spores are two-celled, with or without 
colour. 

Venturis geranii Fr. occurs on the living leaves of Geranium pusilluin , 
G. molle , etc. 

V. rumicis (Desm.). On withering leaves of llume.r. (Britain). 

V. maculaeformis (Desm.). On living leaves of Epi/obium. 

V. vermiculariaeformis Fuck. On withered leaves of Euonymus europaeus 
and Lonicera Xylosteum. 

V. Straussii Sacc. et Bourn. This 1 have found as a parasite on Erica 
carnea in Tyrol. It is also said to cause a disease on Ericaceae in France. 

The various conidial forms at present placed amongst the 
“ Fungi imperfect! ” as Fits iclatl i inn are probably related to 
Venturia. 

Fusicladium dendriticum Wallr. on apple, and F. pirinum 

Lib. on pear, are at present the subject of an investigation at 
the hands of Aderhold , 2 who has, on account of their perithecia, 

1 Bullet. <b la soc. myrol. dt France, 1892 ; Com /it. rani.. 1S89 : lb cm my col. , 
1892. 

2 Aderhold, “Die Peritheeienform v. Fun. dendriticum" Yorluufig Mittlunlung, 
Ber. d. deulsch. hot an. Ges., 1894, p. 338. 


VENTURIA. 


219 


placed them in the genus Venturia. His investigations are, 
however, not quite complete. 

The scab or black spot of apple and pear is a very familiar 
disease in America and elsewhere. It attacks leaves, young- 
shoots, and fruits. Dirty greenish spots appear first, then enlarg- 
ing, they run together, and darken in colour till almost black. If 
the attack occur on young foliage, it may be dwarfed and killed ; 
the newly-formed fruit will in such cases be attacked, shrivel 
up, and fall. If the attack be deferred till the foliage and fruit 
are well advanced, then spotting results and the fruit remains 
hard, perhaps cracks. The conidia are oval, unicellular, and 
yellowish -brown ; they are produced from short conidiophores 



Fig. 107. — Venturia. ( Fv.sicladium ) dendriticv.m forming brown spots on an 
apple ; those still in the earlier stages have a radiate margin and bear conidia. 

The enlarged section shows two rows of large-celled parenchyma of the apple, 
covered by a stroma of pseudoparenchyma bearing conidiophores and conidia. 

(v. Tubeuf del.) 

with warty prominences which grow on spots of leaf or fruit 
(Fig. 107). The peritheeia (as yet described) are distinguished 
by black bristles surrounding the pore, and occur on fallen 
leaves. The asci contain eight greenish ovoid spores with two 
or three cells. 

In addition to the injury to leaves and destruction of young 
fruit, the disfiguration of the apples is a cause of considerable 
monetary loss. Dilute Bordeaux or copper sulphate mixture 
applied before the opening of buds, and once or twice after 


■ 2-10 


ASCOMYCETES. 


“ setting ” of the fruit, is recommended. Xo fungicide should, 
however, be applied towards the ripening season . 1 

Gibellina. 

The spherical perithecia are embedded in the stroma, their 
necks projecting. The asci contain eight brownish spores, 
oblong or spindle-shaped, and bicellular. 

Gibellina cerealis Pass. This parasite of wheat has hitherto 
been fairly common in Italy ; recently it has appeared with 
disastrous effect in Hungary. According to Cavara, it produces 
on the under part of the stems, grey plate-like coatings with a 
brown margin ; these may remain as spots, or enlarge till they 
form a ring round the stem. The perithecia are little black 
points arranged in rows, and embedded under the epidermis, 
except the black projecting necks. The asci have thin walls and 
break up inside the perithecia; they contain eight spores arranged 
in two rows. The spores are spindle-shaped and bicellular, but 
their germination has not as yet been observed. The mycelium 
is found in all the host-tissues, besides forming a stroma-like 
sheath round the stem. The plants attacked become brown and 
limp in early summer, and no fruit is produced . 2 

Cavara recommends early removal and burning of affected 
stems, and the cultivation of crops other than cereals on the 
infected ground. 


Leptosphaeria. 

Perithecia black, rarely with bristles ; at first they are em- 
bedded in the host, without a stroma. The spores occur four to 
eight in each ascus ; they are spindle-shaped and generally 
multicellular by means of cross-walls only. Thread-like para- 
physes are always present. 

Leptosphaeria herpotrichoides de Not. This species, gene- 
rally regarded as a saprophyte, was found by Frank 3 as a 
parasite on rye. The stalks attacked break over at a node or 

'Further details of treatment-experiments are given in Gall and Scribner's 
“ Report on Experiments for 1889," C.S. Amer. of Agrieultiii* IhdUtin u. ; 

also in the Bulletins of various Experimental Stations. The above account has 
been considerably extended by aid from the American literature. (Edit.) 

'-’Cavara (ZtiUchriJt J. Pflanzenkrankhciltn, ill., 1803, p. It!) gives a detailed 
account of this fungus with illustrations. 

'Frank, Z< itsrhrift f. Pflw.rnkrankhtiten, 1S95. 


LEPTOSPHAERIA. 


22 ] 


just over the root, thus resembling the symptoms accompanying 
an attack of Hessian Fly. 

L. tritici Pass, is said by Frank to be destructive to wheat in Germany. 
(See also Cladosporium). 

L. subtecta Wint. 1 In Tyrol the perithecia of this species accompany 
disease of the leaves of Erica carnea. Simultaneously Hypoderma ericae 
Tub. and Sphaeria ericina Tub. were found, the former appearing to cause 
the disease (see p. 234). 

L. anceps Saco. On living branches of Ribes nigrum. 

L. vitigena (Schulzer). On living tendrils of the vine. 

L. circinans Sacc. (see Rhizoctonia p. 201). 

L stictoides Sacc. on Liriodendron tulipifera is an American species. 


Pleospora. 

The black perithecia are not developed on a stroma, and 
are at first concealed in the host-tissues only. They contain 
paraphyses and eight-spored asci. The spores are multiseptate, 
and generally coloured. 

Pleospora hyacinth! Sor . 2 produces black coatings on the 
bulb-scales of hyacinth. The mycelium inside the tissues is 
colourless, but outside is dark red, and its presence causes disease 
of healthy parts. Certain perithecia which appear on the bulb- 
scales in autumn may perhaps belong to this fungus. 

P. tropaeoli Hals, is given as a disease of Tropaeolum in XJ.S. 
America . 3 

P. hesperidearum Catt. The conidial form (Sporidesmium 
hesp.) appears as a black coating on the orange. 

P. ulmi Fr. (var. minor) Allescher, causes a leaf-spot on young 
elm-seedlings, and the leaves drop off prematurely. 

P. napi Fuck, is the cause of rape-smut. Leaf-spots carrying 
conidial cushions (Spor id osmium exitiosum Kuhn) appear on the 
rape and other allied root-crops. 

Other “black smut-diseases” have been ascribed to Polydesmus (Spori- 
desmium) exitiosum ( var Dauci ) on carrot ; Helminthosporium gramineum 
Rabin causing withering of rye and barley leaves ; and Sporidesmium 
putrefaciens Fuck, which attacks and kills the young heart-leaves of beet- 
root. 

1 v. Tubeuf, Botan. Centralblatt, xxi., 1885. 

2 Sorauer, Handbuch d. Pflanzenlerankheiten, n. Aufl., p. 340; and Untersuch. 
iib. die Ringelkrankheit u. d. Russthau d. Hyacinthen. Leipzig, 1878. 

3 A. Jersey A gric. Exper. Stat. Report, 13, 1892. 


ASCOMYCETES. 


ooo 


Dilophia. 

The genus is parasitic and causes swellings. The perithecia 
remain permanently embedded in the tissues of the host-plant. 
The asci contain eight transparent, thread-like, finely-pointed, 
multicellular spores. 

Dilophia graminis Sacc. (Britain). This causes deformity of 
the leaves and inflorescences of wild grasses ; also of rye in 
France, and wheat in England and Switzerland. Fuckel assumes 
a relationship between this species and Dilophospora graminis 
Desrn., but this we regard as doubtful. 

Ophiobolus. 

Perithecia scattered and almost spherical ; they contain para- 
physes and eight-spored asci. The spores are hyaline or 
yellowish, thread-like, and unicellular or septate. The fungus 
is minute and inhabits stems and haulms. 

Ophiobolus graminis Sacc. was indicated by Prillieux, 
Delacroix, and Schribaux as the cause of a cereal disease in 
France. The cereals attacked broke over very easily near the 
ground ; they continued to develop, but produced ears of a poor 
quality, and often quite withered. The disease was designated 
“ maladie du pied des cerdales,” and described in Jour. d’Aqric. 
practique, 1892; also under the name “la maladie du pied du 
bid ” in Travau. i du labor, dt pathol. vdgdtalr rust, agroiwm., 
1890. The perithecia have a curved lateral beak; the asci 
contain eight long, spindle-shaped, multiseptate spores. 

Frank also records this disease as injurious to wheat in 
Germany in 1894. 


GNOMONIEAE. 

Gnomonia. 

Perithecia without a stroma, and generally remaining 
embedded in the host-tissues, with only a beaked opening pro- 
jecting; they contain no paraphyses. The asci have a thickened 
apex with a fine central pore. The hyaline spores consist of 
from one to four cells. 

Gnomonia erythrostoma Auersw. 1 This is the cause of an 

'Frank, Ber. <1. dnitsch. hot an. Gtt. , 1SS6 and 1S87 ; also Zritschryfl J. 
Pjlaiizenkraukhcitci), lSi'l . 


GNOMON I A. 


223 


epidemic disease of the cherry ( Prunus avium and P. Ccrasus ), 
observed for several years past in Xorth Germany and else- 
where. The fungus attacks the leaves, and there the mycelium 
grows. The leaves wither prematurely, but remain all winter 
hanging from the tree by a reddish-brown mycelium. Pycnidia 
and perithecia are produced in the leaves, the latter reaching 
maturity in spring, when the two-celled ascospores are ejaculated. 
The pycnidia contain short conidiophores bearing hook-shaped 
conidia. The fruit is also attacked, and ripens unequally, so 
that the cherries are distorted ; then they crack and rot. 

Frank has succeeded in carrying out artificial infection. This 
takes place in June, and immediately on germination the germ- 
hypha produces an attachment-disc on the host-epidermis, whence 
a hyphal filament penetrates the epidermal wall, grows through 
the cell, and reaches an intercellular space. A thick septate 
mycelium is formed and spreads, especially amongst the spongy 
parenchyma. There is no stroma, and the perithecia hibernate 
on dry leaves. 

Frank recommends the plucking and burning of dead leaves 
hanging on the trees. This must of course be done throughout 
the whole district attacked. In one part of Prussia (Altenlande) 
this precaution was taken twice each winter for two years, 
with the result that the disease, which had long completely 
ruined the cherry crop, disappeared, and the harvest increased 
to its former amount. 

Gnomonia quercus-ilicis Perl . 1 causes brown spots on leaves 
of Quercus Ilex. 


VALSEAE. 

Mamiania. 

Perithecia produced in a black stroma, from which their long 
necks project. The asci have a thickened apex, and contain 
eight oval hyaline spores with one or two cells. 

Mamiania (Gnomoniella) fimbriata Pers. (Britain and U.S. 
America). The stromata of this appear in summer as little 
black cushions on the leaves of the hornbeam ( Cavpinus ). The 
perithecia are developed in these spots, and their long black 
beaks projecting distinctly above the surface of the leaf cause 

1 Berlese, Rivista di Patologia vegetcde, i. 


224 


ASCOMYCETES. 


rupture of the epidermis. Numerous leaves may be diseased 
and each carry many cushions, yet Vuillemin, who described 
the disease , 1 does not believe the host-plant is affected to any 
serious degree. 

M. (Gnom. > coryli Batsch. (Britain and U.S. America 7. The 
black stromata are found in withered spots on the leaves of 
hazel ( Corylus ); as a rule, each stroma carries only one peri- 
thecium with a long beak similar to that of M. fimbriata. 



Fig 108. — Mamiana fimbriata on Carpi a vt Bttvlu*. Leaf of Hornbeam seen 
on lower surface. Stroma (enlarged), with the long Mack necks of the perithoein 
projecting from the ruptured leaf-epidermis, (v. Tubeuf del.) 


Valsa. 

A stroma is generally present, but is of very variable appear- 
ance ; embedded in it are the perithecia, with only their beak- 
like mouths projecting. The spores are hyaline or light-brown, 
unicellular, and generally bent. No paraphyses are present. 

Valsa oxystoma Rehm . 2 This causes disease and death of 
branches of Alnus vindis in the Alps. The symptoms are 
withering and drying up of single branches on an otherwise 
ctreen bush. This disease causes severe loss in the Tyrol, 

O 

1 77/ res el travaux setentifiquefi, 1890. 

2 v Tubeuf. “Zwei Feinde <1. Alpenerle," Forstlich-naturici**. Zeitsehryt, 1S92. 


VALSA. 


225 


where leaves of the alder are dried in summer for use as 
winter-fodder for goats. 

In the branches attacked, a mycelium is developed in the 
vessels of the wood, whereby the supply of water is stopped 
and the bark dries up. Black lens-shaped stromata arise 
under the epidermis of the twig and rupture it. The perithecia 
are produced under the stromata in the bark, and communicate 



Fig. 109. — Valsa oxy stoma on Alnus viridis. A , Portion of branch with stroma 
of Valsa breaking through the periderm at four places. B , Enlarged section 
through a stroma from A. C , Asci and ascospores, isolated from a perithecium. 
D, Portion of younger branch with periderm ruptured by stromata, in which, 
however, the perithecia are not yet developed. E, Enlarged section through a 
stroma of D. (After v. Tubeuf.) 


with the exterior by means of long projecting necks. The 
asci contain eight unicellular spores of a slightly bent, rod- 
like shape. Maturity is reached on the dry dead twigs. 
Externally this disease is identical in appearance with one 
I ascertained to be due to a beetle ( Cryptorhynchus lapatlii), 

p 


226 


ASCOMYCETES. 


the larva of which bores canals in the wood of alders, birches, 
and willows, causing them to die. 

Most of the other species of Valsa cause only leaf-spot, or 
occur on dead leaves. 


Anthostoma. 

The perithecia are embedded in the substratum or stroma, 
and have generally long necks. The asci contain eight brown 
or black, oval, unicellular spores. Paraphyses are always absent. 

Anthostoma xylostei (Pers.) occurs on living and dead 
branches of Lonicera Xylosteum. (Britain). 

Anthostomella pisana Pass, lives on leaves of Chamerops humilis and 
kills them. 


DIATRYPEAE. 

Calosphaeria. 

Xo stroma is formed, the perithecia arising singly or in 
groups in the bark under the periderm; they have often long 
beaks. The asci are club-shaped, and frequently long-stalked ; 
they contain eight or more spores, which are little, unicellular, 
and somewhat curved. 

Calosphaeria princeps Till, occurs on living brandies of 
cherry and plum. (Britain and U.S. America). 

Quaternaria Personii Till, has black perithecia and, according to Will- 
komm, causes death of twigs of beech. (Britain and America). 


MELANCONIDEAE. 

Aglaospora. 

The perithecia are beaked and embedded in the stroma. The 
spores are furnished with appendages. 

Aglaospora taleola Tub 1 ( Dinporth< taltola Fries, and pro- 
bably nearly related to those Mclanconi with appendages on 
their spores, e.g. Mcl. thelebola, previously known as Aglaospora 
tlicl. Tub). (Britain and U.S. America). This fungus causes 
a disease of twigs and young stems of oak which have not 

1 R. Hartig, “ Eine krebsartige Rindenkr&nkheit d. Eiohe,” Font lich-iiat unci. -<s 
Zr itschrij), 1S93. 


AGLAOSPORA. 


227 



Fig. 110. — Examples of Oak-stem attacked by Aglaospom taleota. 1, Portion 
diseased for two years ; a, the portion still healthy ( X -5-). 2, Portion diseased 

for four years ( x ^ ) . 3, Section with spots diseased for four, seven, and ten 

years respectively ( x -}). (After R. Hartig.) 


228 


ASCOMYCETES. 


as yet formed a bark. Portions of the rind become brown, 
dry up, and peel off; this on stronger twigs may be followed 
by a more or less complete occlusion of the wounded part. 
The browning also extends into the underlying wood. The 
mycelium is found both in rind and wood, where it probably 
obtains entrance through small wounds in the bark. In the 
second year after infection, a circular stroma is formed in 
the bark under the periderm. Sickle-shaped conidia are 



Fio. Ill .—Aglaotpora laleola. Portion of cortex with embedded stromata. 
a. Corky layer; b , after removal of corky Layer; c, section of stroma, (x ).) 
(After Hartig.) 



Fio. 112. — Section of stroma of Agloospora. a, Boundary 
of stroma formed of dark brown fungus • mycelium ; 
b , sclerenchyma-strand of the cortex ; r, conidial cushion ; 
d , union of necks of two pcrithecia. (After llartig.) 



Fio. 113. — a, Conidia; b, aseo- 
sporo of Affluosjtot'ti taltola 
( X (After llartig.) 


superficially abjointed from the stromata; while embedded 
in it are groups of pcrithecia with necks which join together 
into one or a few common channels opening externally. The 
asci contain eight spores, which are two-celled and bear five 
thread-like appendages, one on each end, and three round the 
median septum (Fig. 113). 


AGLAOSPORA. 


229 


A g. profusa Fr. (Britain and U.S. America). This occurs 
along with, and probably is some form of Dothiorella ; robiniae. 
Prillieux and Delacroix 1 blame it for killing young twigs of 
Robinia pscudacacia in France. 

Fenestella. 

The stroma is similar to Eu-Vcilsa, and contains several 
long-necked perithecia. The spores, eight in each ascus, are 
coloured and multiseptate, as in Cucurbitaria. 

Fenestella platani Tav., to this is probably related Gloeo- 
sporium nervisequium (Fuck.), the cause of a disease on the 
leaves of Platanus, and described under Gloeosporium. 


(3) DOTHIDEACEAE. 

Phyllachora. 

The perithecia are small and produced in a black stroma 
buried in the tissue. The asci contain eight hyaline, oval, 
and unicellular spores. 

Phyllachora graminis (Pers.). (U.S. America). This species 
causes elongated black swellings on grasses and sedges ( Luzula 
and Carex). The black perithecia occur massed together, and 
embedded in the leaves. The asci contain eight hyaline uni- 
cellular spores. 

Ph. trifolii (Pers.), with conidial form known as Polythrincium 
trifolii Kunz. (Britain and U.S. America). The mycelium 
causes the formation of roundish dark spots on the green 
leaves of clover frequented by it, and death ultimately follows. 
On the spots, especially those on the lower epidermis of the 
leaf, the conidiophores make their appearance as brown septate 
structures, constricted at intervals so as to become rosary-like ; 
they bear terminal, brown, two-celled conidia, the upper cell 
of which is somewhat spherical, and larger than the lower. 

Ph. cynodontis (Sacc.). On living leaves of Cynodon Dactylon. 

Ph. podagrariae (Roth.). On living leaves of Aegopodium Podagraria 
(Britain). 

Some other species are found on withering leaves. 

1 Bulletin svc. mycol. de France, 1S90. 


230 


ASCOMYCETES. 


Diachora onobrychidis (I). C.). 1 This fungus is common 

on sainfoin ( Onobrychis sativa) and Lathyrus tuber oms, causing 
black spots on both surfaces of the leaf. During summer 
pycnidia arise on the spots, and from them are produced spindle- 
shaped conidia (spermatia) with tail-like appendages. Later 
there arise spherical perithecia containing asci arranged in tufts 
on the walls. The asci contain eight oval, hyaline, unicellular 
spores. 

Dothidella. 

The perithecia are black and embedded in the stroma, 
similarly to Phyllaehora. The pale-coloured spores are, how- 
ever, two-celled. 

Dothidella betulina (Fries.). (Britain and U.S. America.) 
The black stromata form spots on the upper surface of 
birch leaves. In these the perithecia arise, and reach maturity 
in spring. The asci contain eight elliptical greenish spores, 
consisting of two unequal cells with rounded-off ends. 

D. ulmi (Duv.). (Britain and U.S. America.) A species 
similar to the preceding, and causing round blistered spots 
of a grey colour on the upper surface of elm leaves. Pycnidia 
( Piggotia astroidea) are formed in summer, perithecia in the 
following spring. 

Dothidea. 

The stromata have the form of black projecting cushions, 
in which numerous perithecia are embedded. The asci contain 
eight greyish or brown spores, consisting of two cells with a 
constriction between them. 

Dothidea virgultorum (Fries.) attacks living branches and 
stems of birch, and develops further on the dead parts. The 
stromata originate in the wood, then breaking through the 
bark, make their appearance externally as large black cushions. 
Whole stems may be covered by these cushions. 

D. sphaeroidea (Cke.) occurs on living needles of juniper. 

Plowrightia. 

The stromata are black, and run together in masses. The 
asci are eight-spored ; the ascospores ovoid or oblong, hyaline 
or light yellow, and two-celled. 

'J. Muller, /Vi ngshe im ’# Jah rbtu'h, 1 SO.'?. 


PLOWRIGHTIA. 


231 


Plowrightia morbosa (Sch.) (Britain and U.S. America). 
Black-knot of the plum tree . 1 In America this is a very 




Fig. 115 . — Plowrightia mor- 
bosa. Ascus, with eight 
spores. Spores in germina- 
tion. Filamentous para- 
physes. (Cop. from Farlow.) 


Fig. 114 . — Plowrightia morbosa. (v. Tubeuf phot.) 


injurious and widely distributed disease of various species of 
Prunus, especially plum and cherry. The living branches and 
twigs become coated with a crust of warty excrescences, and 
at the same time are more or less thickened and deformed. 
A mycelium permeates the tissues of those swollen twigs, and 
forms black crusty stromata in which the perithecia are 
embedded. The perithecia contain simple paraphyses and eight- 
spored asci. The spores consist of a larger and a much smaller 
cell. (Pycno-conidia are produced frequently in artificial culture, 


1 Farlow, Bulletin Bussey Institution, Part v. , 1876. 

Humphrey, Annual Report of Mass. Exper. Station, 1890. 

Lodeman (Cornell Univ. Exper. Station, Bulletin No. 81, 1894) gives 
general account of Black-knot and a Bibliography. 



232 


ASCOMYCETES. 


but are rarely found in natural conditions ; as yet infection 
with these has had no result.) 

[Kernedial treatment must be promptly applied. Trees liable 
to attack should be frequently examined, so that any young 
knots may be early removed. If the disease is of long standing, 
the only remedy left is to remove all knotted branches and 
burn them immediately.] (Edit.) 

HYSTEKIACEAE. 

The ascocarps of the Hysteriaceae, like those of the Discomy- 
cetes, are known as apothecia. They are distinguished from 
those of the Pyrenomycetes and Perisporiaceae in that 
the ascocarp, although formed in or under the epidermis of 
attacked plant-organs, is not a closed structure or Hask opening 
by a pore only ; it is, indeed, at first completely closed, but 
later it, as well as the epidermis covering it, splits open and 
freely exposes the whole hymenium. So long as the apothecium 
is closed, it is filled with paraphyses, between which the 
developing asci gradually wedge themselves. The spores 
are generally thread-like, with a gelatinous membrane. The 
mycelium lives intercellular, and is often parasitic in living 
plants. The apothecia, however, only reach maturity on parts 
which have been killed. In addition to apothecia, little pycnidia 
(spermogonia) are formed, containing small unicellular conidia. 
The Hysteriaceae include the Hystcrineae, Hypodcrinicae, Dickae- 
naceae, and A crospermaceae. 

HYSTERINEAE. 

Hysterographium. 

Apothecia black, highly vaulted, and dehiscing bv a linear 
fissure. The asci are club-shaped and thick-walled ; they con- 
tain eight multicellular spores, which ore at first transparent, 
but later dark-coloured. The branched paraphyses of the 
upper part form a coloured epithecium . 1 

Hysterographium fraxini (Pers.) (Britain). This occurs on 
various Oleaceae and some other species of woody plants. 

’The excipulum of l)e Bury. 


HYSTEROGRAPHIUM. 


233 


Rostrup 1 regards it as a parasite on Fraxinus. Twigs of the 
ash attacked show flat collapsed plates of bark, on which are 
developed pycnidia containing one-celled conidia, and, later, 
the apothecia. On young twigs the diseased part often extends 
round the whole circumference, and causes the death of the 
upper living part. As yet I have only found this fungus as 
a saprophyte. 


HYPODERMIEAE. 

Hypoderma. 


The apothecia are oblong, and at first closed by a thin black 
cover, which opens by a long fissure. The asci are sessile in 



Fig. 116 . — Hypoderma strobicola on Pinus 
Strobus. Ascus containing eight ascospores 
with gelatinous coats ; paraphyses with 
clavate ends. (After v. Tubeuf.) 


Fig. 117. — Hypoderma strobicola. Isolated 
ascospores : with and without a gelatinous 
coat, and one- or two-celled. (After v. 
Tubeuf.) 


some species, but have a delicate stalk in others. The spores, 
eight in each ascus, are never long and thread-like, but always 
much shorter than the asci, and two-celled when mature. The 
paraphyses have button-shaped or hooked ends. 

Hypoderma strobicola 2 (Rostr.), Needle-blight of the Wey- 

1 Rostrup, Fort.satte Undersoeqelser ov. Snyltesvamves Anarch paa SIcov- 

traeerr.e, 18S3. 

-Rostrup, Fortsalte Undersoeqelser, 1S83. 

v. Tubeuf, Beit. z. Kenntniss d. Baumkrankheiten, 1888 ; also Botan. 
Ce.ntralhlatt, xli,, 1890. 

Note : \\ hen I decided to place Lophodermium brachysporum under the 
genus Hypoderma, there already existed a Hypoderma brachysporum Speg. 
(1887). f or the future I shall therefore call Lopih. brachysporum Rostr. as 
Hypoderma strobicola. 


234 


ASCOMYCETES. 


mouth pine. According to the observations of Eostrup in 
Denmark, and myself in various localities of Germany, this 
is a dangerous parasite on Pinus Strains. 
It kills the needles and young shoots, 
and may devastate whole tracts of forest. 
The diseased needles become brown in 
summer, and fall off during next winter. 
On them are produced apothecia containing 
club-shaped asci and paraphvses with button- 
shaped ends. The eight spores of each ascus 
are at first unicellular, later apparently bi- 
cellular, and enclosed in a very mucilaginous 
coat. The asci have an average length of 
120/u, the spores 20u, and when swollen 
28 to 30 fi- 
ll. pinicola Brunch. 1 forms linear apothecia 
on needles of Pinus sylvestris. 

H. ericae Tubeuf. 2 3 In Tyrol and Northern Italy, this fungus 
causes a disease on Erica carnea. It is common and epidemic, 
causing death of the leaves. 



Fig. 118 . -Leaf of Erica 
camca with apothecia of 
ffj/poderma triccu on the 
lower surface. 1, An 
entire and a dehiscing 
ascus ; a two-celled asco- 
spore. (v. Tubeuf del.) 


Hypodermella. 

Similar to Hypodervia, except that the spores are pear-shaped 
and unicellular; they occur four in each ascus, and are shorter 
than it. 

Hypodermella sulcigena (Link) has four long, club-shaped. 

unicellular spores. Eostrup regards it as parasitic on Pinus 
montccna and P. sylvestris, its mycelium being found in living 
green needles, and causing their death. 

Hyp. laricis Tubeuf." This is a new fungus of the larch- 
needle found by Tubeuf on the Sonnenwendsteiii (Bavaria) in 
September, 1894. It was present in large quantity on larches 
on the upper part of the mountain, and was in every way so 
decidedly parasitic in character, that there is little doubt as to 
its being an epidemic disease. The full-grown needles on many 
of the foliar spurs had died off and turned brown. The 

1 Brunchorst, .Vo'/A norsb ukorsi/rjiloin nu in Bergnis J/im., 1 S92. 

2 v. Tubeuf, Botan. Centralhlalt , xxi., ISSo. and i.xi.. 1 S95. 

3 Rostrup, For/sath Undersotgtlser, 18S3. 


HYPODERMELLA. 


235 


apothecia were present on the upper surface of the needles as 
isolated black spots or united into lines ; they dehisce by an 
elongated fissure. The asci are cylindrical with rounded apices, 
and measure about 110 m in length; they are almost sessile. 
Each contained four hyaline, unicellular, club-shaped spores 



Fig. 120 . — Hypodermella larids. Larch- 
needle with apothecia on the under side. 
A, Paraphyse, and an ascus containing 
four spores. B, Isolated (enlarged) asco- 
spore in its gelatinous coat. (v. Tubeuf 
del.) 


Fig. 119 . — Hypodermella sulcigena. The 
apothecia form black lines on the needles. 
Ascus containing four spores (enlarged). 
Single spore with a gelatinous covering 
(still further enlarged). (Cop. from 
Rostrup.) 


(66 m x 16/x) with a gelatinous membrane. The paraphyses 
are simple hyaline filaments, shorter than the asci. 


Lophodermium. 


The oblong apothecia are embedded in the host-tissues under 
a thin black cover, which breaks by a long fissure. The club- 
shaped asci contain thread-like unicellular spores, with a 
mucilaginous membrane. The paraphyses are sometimes septate 
and furnished with hooked or button-shaped ends. The spores 
reach maturity on killed portions of plants, and are forcibly 
ejaculated. The formation of pycnidia (spermogonia) precedes 
that of apothecia. Many members of this genus are destructive 
enemies of plants. 

Lophodermium pinastri (Schrad.). 1 Pine-blight or needle- 
cast. (Britain and U.S. America.) This disease of the Scots pine 
( Pinus sylvestris) is very injurious to young plants, especially 
those in nurseries. 

1 Hartig, Diseases of Trees, Eng. edit., 1S94. 

Frantl, Flora, 1877 ; also, Forstwiss. Centralblatt, 1880. 


236 


ASCOMYCKTES. 


“ Casting ” or premature withering and fall of needles is not 
uncommon in nurseries of pine. Amongst some of the causes 
which lead to this are : l frost, drought in winter on frozen 
ground free from snow, drought in summer on dry soil, over- 
crowding of plants in the nursery, and, finally, a “ casting ” due 
to fungi. 

The symptoms in the case of the present fungus are spotting 
and withering of the needles, due to the presence of a mycelium 
inside them. In early autumn, or later if the weather be dry, 
the pycnidia (spermogonia) make their appearance as little black 
prominences containing tiny unicellular conidia. The fiat black 
apothecia are developed later, on first-year seedlings during 
the first autumn, or on older plants during the second autumn, 
but generally they do not appear till the third year ; they 
reach maturity on needles still attached, more frequently, how- 
ever, on fallen ones. Dehiscence consists in the rupture of 
their delicate black covering, through pressure of the swelling 
asci and spores in damp weather. The asci are club-shaped 
and contain eight thread-like one-celled spores, more or less 
twisted round one another. The septate paraphyses have a 
slightly bent point. 

Diseased seedlings die off, generally without loss of their 
leaves. Two-year-old and older plants are always weakened by 
the loss of needles, and in severe cases are killed. On such, 
the “ casting ” or sudden fall of all infected spurs and needles 
takes place in spring. The mycelium often makes its way 
from the needles into the tissues of the shoot, and then death 
of the whole plant soon follows. Disease of the needles of 
old trees may also occur without inflicting much damage on 
the trees themselves ; they will, however, act as centres for 
infection of younger plants, particularly those in seed-beds 
and nurseries in the vicinity. 

Confirmatory experiments on infection of pines by this 
Lophoclermium were first carried out by l’rantl, later by Tursky 
and Hartig. 

The disease appears with such virulence and frequency, that 
the whole of the young pine-growth of a locality may be 
destroyed. It is thus a most dangerous disease, and at the 
same time one difficult to combat. Districts which have 

1 Holzner gives a summary of numerous theories on leaf-cast, (Freising, 1S77). 


LOPHODERMIUM. 


237 


suffered by it should, where other soil conditions permit, be 
planted with Weymouth pine ( Pinus Strobus ) and the Douglas 
fir ( Pseudotsuga Douglasii), which are, as yet, exempt from 
attacks of this parasite. Infection would seem to be brought 
about chiefly by westerly winds (in Germany), which carry 
diseased leaves or fungus-spores from infected 
places. Large areas run greater risks than 
small patches or young trees naturally sown 
out. Seed-beds of Scots fir should not be 
placed under the drip of older trees of the 
same kind, particularly if this fungus is 
known to exist there. Shelter- belts of other 
trees often afford much protection from this 
disease . 1 

Lophodermium macrosporum Hartig 2 
(. Iiysterium ). (U.S. America). Scab or rust 

of the spruce. This disease exhibits itself 
in various ways. Frequently the needles of the preceding 
year turn brown in spring, and perithecia are produced in 



Fig. 122. — Lophodermium macrosporum. Section through a mature dehiscing 
apothecium. (After R. Hartig.) 



1 2 


Fig. 121.— 1, Lophoder- 
mium macrosporum on 
Spruce, (v. Tubeuf del.) 

2, Lophodermium ahi- 
etis on Spruce. (After 
Rostrup.) 


summer, reaching maturity on two-year-old needles. Again, the 
needles of the two-year-old shoots become brown in autumn, 
and perithecia appear on them in the following summer, 

1 Preventive measures are discussed in greater detail in Prof. Somerville’s 
translation of Hartig’s Diseases of Trees, p. 115. 

2 R. Hartig, Wichtige Krankheiten d. Waldbdume, 1874. 


238 


ASCOMYCETES. 


ripening in the spring of the fourth year. Or, again, a 
“ casting ” of brown one-year-old needles may take place in 
autumn. 

The disease is found everywhere, but in some parts ( e.g . in 
the forests of Saxony 1 ), it is exceedingly common and very 
dangerous. The apothecia are developed as long, shining, black 
swellings on the two under surfaces of the quadrangular needles 
(Fig. 121). The club-shaped asci emit 
thread-like spores with gelatinous coats. 
The ascospores produce a strong germ-tube, 
which grows inside the needles to an 
intercellular mycelium- without haustoria. 
Browning and shrinkage of the cells of 
attacked needles soon follow. The myce- 
lium also penetrates into the cells of the 
epidermis, and develops there a coil of 
hyphae, which, under a black membranous 
cover, forms an apothecium containing 
paraphyses and club-shaped asci (Fig. 
122). When ripe, the apothecia rupture 
the overlying epidermis. Little black 
pycnidia (spermogonia) may also occur on 
diseased needles. 2 On needles which have 
been prematurely cast, only little spherical 
apothecial knobs will be found. 

According to Hartig, the effects of this 

Flo. 123. — Lophodermium r . 

nuKrotporum on spruce, fungus on the cells of attacked needles is 

Germinated ascospores: . . . re.i r , , 

some have germinated very interesting. It the disease of the 

inftide the ascus. (After ,, . 1 . i • i 

h. Hartig.) needles appears m autumn, the cells, which 

at this time are void of starch, become 
brown and die. If the disease attacks in May, when the 

needles are rich in starch, their death ensues soon, but the 
starch only disappears gradually from October onwards, as it 
is used up by the fungus-hyphae. If the disease appears in 
spring, when starch-storage is just beginning, the cells already 
attacked become quite full of starch, whereas the other cells of 
the same needle remain empty. 

1 Nobbe, Her. d. si tchsi aches Forst rereins Vcraammlung ;i / Schandnu, 1S!M. 

5 Another ascomycetous fungus — Xatria piniperda Rehm — occurs alone or 
together with this species ; Rehm regards it as parasitic (Hcdtciijia, 1892, p. 302). 



LOPHODERMIUM. 


239 


Lophodermium nervisequium (D. C.) 1 (U.S. America). This 
very common fungus attacks both old and young silver firs. 
The needles die after becoming brown, and remain for a long 



Fig. 124. — Lophodermium nervisequium 

on Abies pectinata (Silver Fir). 1, Under 
surface of needle with apothecia. 2, 
Upper surface with pycnidia. 


Fig. 125. — Lophodermium nervisequium. Section 
of a needle of Silver Fir. b, Pycnidium on 
upper surface shedding conidia. a, Apothe- 
cium on the lower surface. (After R. Hartig.) 



Fig. 126. — Lophodermium nervisequium on Silver Fir. Portion of a ripe apothe- 
cium. a a. Filamentous paraph yses ; rod-like cells (conidia?), k, abjointed from 
the apex of the paraphyses ; the asci contain eight spores about half as long as 
the ascus itself, four occupying the upper half, four the lower ; c, a rudimentary 
ascus ; some mature spores possess a gelatinous coat, others do not ; spores 
escape by an apical opening, e, or by rupture of the ascus,/; two germinating 
spores are also shown, one with a gelatinous coat, the other without. (After 
R. Hartig.) 


time hanging on the twigs. The disease varies in its develop- 
ment on the mountains and lowlands, according to climatic 
conditions. 


1 R. Hartig, Wichtige Kranhheiten, 1874. 


240 


ASCOMYCETES. 


The mycelium lives intercellular, and produces the same 
effects on the cells of the fir-needles as those of Loph. macro- 
sporum on the spruce. The mycelial hyphae penetrate into the 
epidermal cells and form a cushion, which bursts the epidermis 
and gives rise to numerous straight conidiophores, with very 
small, oval, unicellular conidia. The apothecia are developed 
while the needles are on the tree or after they have fallen ; 
they form shining black stripes on the middle nerve of the 
lower surface of the needle (Fig. 124). The thread-like spores 
have a mucilaginous coat, and are ejaculated from club-shaped 
asci (Fig. 126). Pycnidia (spermogonia) are often produced 
before the apothecia as long wavy bands on the middle nerve 
of the upper surface of the needle (Fig. 125). 

L. juniperinum (Fries.) (Britain and U.S. America). A 
common species on dead needles of Juniper communis, also on 
needles on the branch ; I have, however, never seen it in such 
mass as to believe it to be a dangerous parasite. 

L. gilvum Rostrup 1 attacks and kills living needles of the 
Austrian black pine. 

L. laricinum Duby. The pycnidia and apothecia of this 
fungus are common on dead needles of larch, but parasitism has 
not been proved. 

L. abietis Ilostr. A species found by Rostrup on needles of 
spruce, causing yellow spots and then lai’ge black points (Fig. 
121 , 2 ). 


DISCOMYCETES. 

The Discomycetes have an apothecium of varying shape, but 
always more saucer-like than spherical. The ascocarp, at first 
a closed structure, opens sooner or later and exposes tin' 
hymenium. The apothecium is composed of two distinct portions 
of mycelium. The essential part, often called the hymenial 
layer, consists of hyphae which give rise to the asci. The 
remaining portion of the ascocarp forms a support or envelope 
for the hymenium; it consists of a pseudoparenchyma, and may 
be differentiated into a sub-hymenial layer or hypothecium with 
its hyphae interwoven with those of the hymenium, and a 
lateral portion or excipulum usually more or less cup-shaped. 


Rostrup, Fortm*t< Undersoegihcr, 1 SS.'t. 


DISCOMYCETES. 


241 


The paraphyses are developed from the mycelium of the 
envelope and occupy the interior of the ascocarp, while the 
asci arise later from the ascogenous hyphae and force their way 
in. The formation of asci and paraphyses may go on for a 
long time. Periphyses are not produced. 

The Discomycetes include five divisions, the Phacidiaceae, 
Stictideae, Tryblidieae, Dermateaceae, and Pezizeae. Many of 
the species included in these are parasitic on cryptogamic 
plants to form lichens, the majority are saprophytes, and only 
a few isolated groups are true parasites on higher plants. The 
latter belong to the Phacidiaceae, Dermateaceae, and Pezizeae. 


(1) PHACIDIACEAE 

The apothecia are black and thick-walled, at first embedded 
in their substratum, but later breaking through it. The asco- 
genous layer is spread out on a delicate flat hypothecium. 
The black apothecia of the species of Phacidmm are frequent 
on leaves and needles. Eelnn divides the group into two 
families : the Eupliacidieae and the Pseudophacidieae. 


EUPHACIDIEAE. 

The apothecia are embedded in the tissues of the host ; the 
superincumbent layers of the. substratum forming over them a 
blackish membranous plate, which is ruptured into lobes and 
exposes the black apothecial disc. 

Phacidium. 

The apothecia are fused with the superincumbent layers of 
the host-plant, and the black cover so formed is split into 
several lobes. The club-shaped asci contain eight colourless, 
unicellular, ovoid or spindle-shaped spores. The paraphyses 
are filamentous. The pore of the ascus is coloured blue by 
iodine. 

Phacidium repandum Fr. (Britain). Occurs on living leaves 
and stems of Aspcrula odorata, Galium mollugo, and other 
Rubiaceae. The pycnidial form is probably Phyllachora 
punctiformis Fr. 

Q 


242 


ASCOMYCETES. 


Schizothyrium. 

The roundish or oblong apothecia dehisce by lobes. The club- 
shaped asci contain oblong, hyaline, two-celled spores. 

Sch. ptarmicae Desm. (Britain). This occurs as a parasite 
on living green leaves and stems of Achillea Ptarmica. The 
apothecia form little black points, which on rupturing break 



Fig. 127 . — Schizothyrium ptarmicae on Achillea Ptarmica. (v. Tubcuf del.) 

up the epidermis into lobes. The thick asci contain two to 
four large two-celled spores. I'araphyses are present. A pycnidial 
form is known as Lcptothyrium ptarmicae (Sacc.). 

Rhytisma. 

The fungi of this genus live in the tissues of living plants and 
form sclerotial cushions as isolated black spots. In these places 
the pycnidia are developed, and are followed by apothecia after 
the death of the leaves. The apothecia open by a fissure, and 
contain thread-like paraphyses and club-shaped asci with eight 
needle-shaped spores, which are septate when mature. 

Rhytisma acerinum (Pers.) (Britain and I'.S. America). 
Towards the close of summer, the large black spots caused 
by this fungus on leaves of various species of Acer (sycamore 
and maple) are by no means uncommon. Pycnidia (.1 fclasmia 
acerinum Lev.), containing little unicellular conidia. are first 
produced under the cuticle, while the epidermis and under- 
lying cells become filled with mycelium till a black sclerotium 


RHYTISMA. 


243 


is completed. In the following spring, the sclerotium-spots 
on the fallen leaves have become thicker and superficially 
wrinkled. At this stage the apothecia are produced, and 
dehisce by fine elongated fissures ; they contain club-shaped 
asci and thread-like paraphyses with hooked ends. The thread- 
like ascospores are ejaculated with considerable force, and reach 



Fig. 128 . — Rhytisma acerinum. Two • apothecial cushions on leaf of Acer 
campestre in first summer. A, Leaf -apex of Acer platanoides with the mature 
apothecial cushions as seen in the second summer, with their characteristic 
wavy marking, (v. Tubeuf del.) 

maturity in May or June. According to Klebahn , 1 the spores 
have a mucilaginous membrane, but this does not throw much 
light on the problem of how they reach the leaves of trees ; 
wind, however, would seem to be the agent for distribution. In 
three weeks after infection, leaves show yellow spots ; in eight 
weeks the pycnidia appear. 

1 Botan. Centralblatt, lviii. , 1S94, p. 321. 


244 


ASCOMYCETKS. 


The disease is best combated by prompt removal of fallen 
leaves in autumn; where this rule is followed Rhytisma is seldom 
found (see p. 71 ). 

Rhytisma punctatum (Pers.) (Britain and U.S. America). 
Whereas the spots of the Rhytisma just considered are large, 
those of this species seldom exceed a few millimetres. They are 



Fi<4. 129 — Rhytisma punctatum. Leaf of Acer Pseudoplatanus with unothecia; 
the leaf in yellow, but the spots enclosing the apothecia are still green, 
(v. Tubeuf del.) 


black in colour, angular, and scattered over the whole leaf- 
surface. After the leaf has turned yellow, portions of it sur- 
rounding spots of this Rhytisma retain their green colour, so 
that we have black spots on green islands in the yellow leaf. 

The sclerotia dehisce by valves. The apothecia contain thread- 
like paraphyses and asci. The asci are club-shaped and contain 


RHYTISMA. 


245 


eight needle-shaped unicellular spores ; pycnidia (spermogonia) 
with little unicellular conidia are also formed. 

The fungus attacks leaves of sycamore (Acer Pseudoplatanus ), 
the black spots making their appearance in September. The 
apothecia ripen on the ground during the following summer . 1 



i 


Fig. 130. — Sections of Maple leaves 
showing the upper epidermis ruptured 
by 1, Rhytisma acerinum ; 2, Rhytisma 
punctatum. 



Fig. 131. — Rhytisma symmetricum Miill. Two 
leaves of Salix purpurea with stromata. A, The 
upper side. B, The lower side. C, Longitudinal 
section through the same leaf, showing numerous 
apothecia on the upper side, fewer on the lower ; 
the shaded middle part represents leaf-tissue, 
the remainder is the light fungal stroma in 
which the darker apothecia are embedded, 
(v. Tubeuf del.) 


Rh. salicinum Pers. (Britain and U.S. America). Thickened 
black wrinkled spots appear frequently on living leaves of various 
species of willow, e.g. Salix Caprea, S. cinerea, etc., also on some 
alpine willows, e.g. S. reticulata. These contain apothecia of this 
fungus, which reach their full maturity during the second 
summer. 

1 Dyscomycopsis rhytismoides Abtill. Black spots similar to those of Rhytisma 
appear on the leaves of sycamore. The black crusts are here only subcuticular . 
and enclose a transparent tissue from which large spherical spores are produced. 
The systematic position of this fungus is unknown. 


246 


ASCOMYCETES. 


Rh. symmetricum J. Muller (Rh. autumnale Schroeter ) 1 is a 
form occurring on Salic purpurea and recently separated as a 
distinct species. This willow, one of the best for cultivation, 
may often be seen with its leaves covered with black spots, 
and the disease may spread over every tree in a nursery. 

The apothecia are found on the upper surface of the leaf, 
on black, shining, and much wrinkled cushions. In addition, 
black apothecial cushions are developed on the under surface 
of the leaf, which is not the case with any other species of 
Rhytisma. According to Schroeter, the spores ripen in autumn 
on still living leaves. 

(This species may be synonymous with Rh. australe Dur. et Mont, on 
Salix purpurea in Algeria.) 

A species which causes little thick cushions on Salix Caprea has been 
called Rhytisma umbonatum Hoppe. 

Rh. andromedae Pers. occurs on leaves of Andromeda polifolia. (Britain 
and U.S. America). 

Rh. empetri Fries, on leaves of Empetrum nigrum. (Britain). 

Rh. juncicolum Rehm on Juncus Hostii. 

Rh. urticae Fr. on stems of Urtica dioica. (Britain and U.S. America). 

Rh. bistortae D. C. on Polygonum viviparum in France, Greenland, and 
America. 


PSEU DOPH ACI DIEAE. 

The apothecia are at first embedded in their substratum, 
under the superincumbent layers of the host-tissue, and form 
blistered patches ; on rupture, this cover forms a rim round 
the apothecial cushion; the excipula of the apothecia themselves 
are membranous, generally black, and dehisce by lobes or 
fissures on the apex. 


Cryptomyces. 

The apothecia break out from the substratum as black crusts. 
The asci contain eight oval, unicellular, colourless spores. The 
paraphyses are thread-like and septate. 

Cryptomyces maximus Fries . 1 (Britain and United States). 
This fungus lives parasitic on twigs of various species of willow 

1 J. Muller, “Zur Kenntnias <1. Rmi/.elachorfa," Prinyxheitn'* Jahrbuch, 1S9.4. 
.Schroeter, Flora r. SchJtnien, 1S94. 

* Both appear to be identical with Rh. amphiyenum Wallr. (Flor. Crypt, u. 412). 
- Tulasne, Select, fungorum Carpoloyia, in. 


CRYPTOMYCES. 


247 


especially Salix incana, but also on S. purpurea. When the 
black apothecial cushions break out through the bark, the twigs 
of the host-plant are frecpiently still green and leaf-clad. 

The apothecia originate in the lower bark and so loosen 
the epidermal layers as to cause the appearance of yellow spots. 
Black centres appear in the spots, due to the formation of a 




Fig. 132 . — Cryptomyces maximum. 1, Cross-section of a twig of Salix incana, 
with stroma a b ; the mycelium occupies the rind and bast into the cambium, so 
that a wood-ring for the current year has been only partially developed ; the 
shaded part between a and 6 is an aerating tissue, formed of loose hyphae, which, 
with a, forms the stroma proper ; b, the ascogenous layer. (Lens-magnification.) 
2, Asci, showing a dry ascus ; one to which water has been added, so that it is 
elongating ; one ruptured and ejaculating spores. 3, Young stromata in spring, 
still covered by the epidermis of the Salix. 4, Willow twig after detachment of 
the patches of Cryptomyces in autumn, (v. Tubeuf del.) 


black apothecial cover underneath the epidermis. On rupture 
of the epidermis, black apothecial cushions emerge and cover 
large areas of the living twigs. Bain causes the apothecia 
to become gelatinous, and to swell considerably ; on drying 
the cushions roll up and fall off, leaving scars in the bark 
(Figs. 132, 4). 


248 


ASCOMYCETES. 


A longitudinal section through a cushion exhibits a thick 
hypothecium, consisting of a close pseudoparenchyina of hyaline 
fungal cells, which permeate every tissue of the bark and cause 
death of the cambium ; above this comes a looser layer with 
many air-spaces, and over this the layer from which the asci 
and paraphyses arise. 

The asci contain eight oval unicellular spores with distinct 
cell-nuclei. When a section is placed in water, a very 
evident swelling takes place, and the asci elongate to twice 
their original length. I have not observed ejaculation of 
spores, but rupture of the asci occurs in water-preparations 
and the spores are set free in large numbers. The spores 
probably germinate and infect young shoots, the mycelium 
hibernating there. 

The effects of this fungus are death of diseased twigs of 
willow above the spot where a sporogenous cushion is 
formed. 

This species is also said to frequent Corpus in America. 

Cryptomyces pteridis (Rebent.) occurs on fronds of Ptn-is 
aquilina, but whether a parasite or not is as yet uninvestigated. 
The asci ripen after the fronds have passed through the winter. 
To this belongs the conidial form Fusidium pteridis Rabh. 

Clithris. 

The apothecia, at first spherical, become oblong, and break 
through the superincumbent layers by a lobed fissure. The 
apothecial disc is oblong and flat. The club-shaped asci contain 
eight hyaline spindle-shaped or thread-like spores, with one or 
more cells. The paraphyses are thread-like. The majority of 
this group are saprophytes. 

Clithris (Colpoma) quercina (Pers.) (Hritain). According to 
Schroeter , 1 this causes disease and death of living branches of 
oak. The oblong apothecial discs are greyish-white, and covered 
at first by a brownish-grey wall which, later, becomes ruptured. 
The ascospores are simple. Cylindrical pycnidia, with somewhat 
bent conidia, are also produced. 

Cl. juniperi (Karst.) occurs on living twigs of juniper. Nothing is 
known of its parasitism. 


1 Schroeter, Pihc Schtesien -s, 1893. 


DOTHIORA. 


249 


Dothiora. 

The spherical apothecia are embedded in the substratum, which 
they rupture into lobes, while they themselves dehisce by 
irregular fissures. The club-shaped asci contain eight colourless 
or yellow, club-shaped or spindle-shaped, multicellular spores. 
Paraphyses are never present. 

Dothiora sphaeroides (Pers.) is regarded by Eostrup as the 
cause of a disease of the Lombardy poplar ( Populus pyramidalis), 
in which the branches, particularly those of the upper part 
of the tree, die one after another till all are gone. The spores 
are club-shaped and constricted at the middle ; each half is 
divided by four or five cross-septa, and each cell so formed 
is again subdivided by a longitudinal septum. 

Vuillemin ascribes the same disease to Didymosphaeria 
populina Vuill. (see p. 218). 

According to Eehm, Do. spliaeroides also occurs on Populus 
tremula, and is distinguishable from Do. mutila (Fr.) on both 
Populus italica and P. tremula. 


Heterosphaeria. 

The spherical apothecia are at first embedded, but later emerge 
through the covering layers and dehisce, their apices breaking 
up into teeth-like lobes ; they are dark-brown or black in colour. 
The asci are club-shaped and contain eight spores, which are 
colourless, oblong or club-shaped, and consist of one, two, or 
four cells. Iodine colours the pores of the asci blue. The 
paraphyses are colourless and thread-like. 

Heterosphaeria Patella (Tode). (Britain and U.S. America.) 
The asci contain eight bicellular spores. The paraphyses are 
thread-like and septate, some being forked or branched ; they 
bear scalpel-shaped conidia. 

The mature apothecia are found chiefly on the stems of 
various Umbclliferae, c.g. Daucus Carota, Anethum graveolens, 
Petroselinum sativum, Pastinaca, etc. A variety alpestris occurs 
amongst the mountains on Heracleum Sphondylium, also on 
Gentiana lutea, Veratrum viride, etc. Eehm and others believe 
that the fungus attacks living green parts of plants, and reaches 
maturity in the following year on the killed organs. 


250 


ASCOMYCETES. 


Scleroderris. 

A black stroma is formed in the bark of twigs attacked 
by this fungus, and thence the apothecia break out in great 
numbers, at first as closed spheres, later as stalked open 
cups with finely lobed rims. The asci are cylindrical or club- 




Flti. VU,—&cUrodtrrit fuliginota on living twig of Salic alba. 
a, Three apothecia, two in section, the third seen from above, 
showing the cross-like fissure. B, Sections of diseased branches, 
whose growth has been arrested in the shaded ]>arts ; on the 
dead bark apothecia are present. Asci. spores and paraphysos, 
(v. Tnbeuf del.) 


Flo. 133.- ScUroderri* futi- 
aiiiota on living twig of 
Salix Caprca. (v. Tnbeuf 
del.) 


shaped, and contain eight colourless spores which are club- 
shaped, needle-shaped, or thread-like, and divided by septa into 
four to eight cells. The pores of the asci are coloured blue 
by iodine. The paraphyses are thread-like. 


SCLERODERRIS. 


251 


Scleroderris fuliginosa (Fries). (Britain and U.S. America.) 
This was considered to be a saprophyte till my attention was 
directed to its injurious nature. It occurs on living branches 
of Salix Caprea, S. triandrcc, S. albct, etc., and brings about 
their death. The black crusts, on which the apothecia develop, 
appear both on weakly twigs and strong branches. The my- 
celium makes its way through the tissues to the cambium, which 
it kills, causing this and neighbouring parts to become brown. 
Adjacent parts, as yet unattacked, continue at first to grow in 
thickness, but they too are gradually killed. As a result, the 
twigs attacked grow irregularly according to the extent and 
number of diseased places (Fig. 134); and when all or most 
of the lower tissues of a twig are killed, the higher parts 
die off with their leaves. Wherever the fungus appears, many 
trees are generally attacked. 

Sc. aggregata (Lasch.) develops on the living stems of Bhinanthaceae 
and matures on the dead. 

Sc. ribesia (Pers.) is a common species on twigs of red and black currant, 
but whether parasitic or not is unknown. 


(2) DERMATEACEAE. 

The apothecia are developed at first either under the sub- 
stratum or altogether superficially. The ascogenous layer 
extends over a thick hypothecium. 

The Dermateaceae contain the Cenanqieae, Dermateae, Patel- 
lariaceae, and Bnlgariaceae. 

CENANGIEAE. 

Apothecia at first embedded, then exposed. They are sessile, 
clavate or cone-shaped, and broaden out to discs on opening. 

Cenangium. 

Apothecia globose ; on dehiscence at first cup-shaped, but 
afterwards flatter and more saucer-shaped, with entire margins; 
they may occur singly or massed together. The club-shaped 
asci contain eight colourless, oblong, unicellular spores, and 
filamentous paraphyses with thickened apices. 

Cenangium abietis (Pers.). (Britain and U.S. America.) Tins 
fungus is usually a saprophyte, but Thumen suggests it as an 


252 


ASCOMYCKTES. 


occasional parasite. Schwarz 1 has recently described it as 
attacking pines, weakened by an impoverished water supply to 
the twigs and by other unfavourable conditions. It appeared 
for a time as an epidemic in the pine forests of Germany, but 
very soon disappeared again. 

The symptoms of disease were, withering of twigs in spring 
from the apex downwards into the region several years old. 
The epidemic had been previously noticed in the spring of 
1892, and was described by Hartig, who, along with Kienitz, 
regarded it as a result of the long dry preceding winter. The 
disease has never been observed on pines under five years old, 
and serious injury only results when the fungus is accompanied 
by damage done by insects. The apothecia containing the asci 
are generally produced only on dead twigs and needles. 

Schwarz regards as a conidial form of this species, Brun- 
chorstia destruens Erikss., which will be described in gi'eater 
detail amongst the “ Fungi imperfecti.” In addition to Brvn- 
chorstia, other pycnidia with unicellular conidia occur. 


DERMATEAE 

The apothecia, at first spherical and embedded in their host, 
break out in clumps; they are generally short and thick-stalked, 
and open to form a roundish saucer-shaped disc with an un- 
broken rim. The hypothecium is thick and often coloured. 

Dermatella. 

A stroma is developed under the bark of the attacked parts 
of the host, and in it originate dark brown apothecia with 
short thick stalks. The bark is ruptured and the apothecia 
emerge as flat, expanded, saucer-shaped discs with a complete 
rim. The asci are club-shaped and thick-walled. The spores, 
at first unicellular, later multicellular, are large and colourless 
or brownish. The paraphyses are septate and generally forked : 
they often form a coloured epithecium. 

Dermatella prunastri (Pers.) (Britain and IS. America). 
According to Ludwig, this lives as a parasite on the living 
hark of plums, apricot, sloe, and other species of Pntnrn. 

1 Schwarz, Die ErkrauJniny <!. Kie/em durch Cenangiiim abietin, Jena, 1895. 


DEKMATELLA. 


253 


Apothecia and pycnidia ( Sphaeroncma spurium Fr.) are both 
developed. The ascospores are one-celled and hyaline. 

[Wagner 1 adds the following species found by him in Saxony as more 
or less marked parasites : (Edit.) 

Dermatea (Pezicula) cinnamomea (Pers.) on Quercus. It attacks the 
rind in places injured by deer, and causes injury to the trees. 

D. (Pez.) carpinea (Pers.) kills many young hornbeams ; it probably 
obtains entrance through wounds. 

D. (Pez.) acerina Karst, is a doubtful parasite on Acer Pseud' o pi at anus. \ 

BULGARIACEAE. 

Bulgaria polymorpha Wett. (B. inquinans Fr.) (Britain and U.S. 
America). A dangerous enemy of the oak , 2 causing death. Researches 
into its parasitism are still wanting. The sporocarps develop on dead 
bark, especially of beech. 


(3) PEZIZEAE. 

The apothecia are never embedded, but appear as saucer- or 
cup-like structures on tire substratum ; they are fleshy or waxy, 
and often of bright colour. The hvpothecium is very strongly 
developed. 

The families included in this group are : Mollisieae, Hclotieae, 
Eupezizeae, and Ascoboleae. Of these, all except the last con- 
tain parasitic forms. The Mollisieae and Hclotieae contain also 
a number of lichen-fungi not considered of sufficient practical 
value to be included here. The Ascoboleae live as saprophytes on 
animal droppings. 


MOLLISIEAE. 

The apothecia generally sit free throughout their whole 
existence on a close, firm substratum of hyphal tissue, or they 
may be sunk in the host and break out later ; they are at 
first closed and spherical (rarely tapering downwards), but after- 
wards open and expose a cup-like, saucer-shaped, or flat disc of 
asci. The disc is waxy and soft ; externally it is brownish 
and generally smooth ; exceptionally it may be downy or beset 
with short hairs or bristles. The sporocarps are brown and com- 

1 Zeitsch. f. PJlanzenkrankheiten, 1896, p. 76. 

- Ludwig, Centrcdblatt f. Bacteriologie it. Parasilenkunde ; also, Lehrbuch d. 
tiiederer Kryptogamen. 


254 


ASCOMY CETES. 


posed of pseudoparenchyma, which, towards the margins, becomes 
more elongated and prosenchymatous. Hypothecium generally 
poorly developed. 


Mollisia. 

The sessile brownish apothecia on opening generally exhibit a 
flat, saucer-shaped, transparent stratum of asci. The spores are 
unicellular, hyaline, and spindle-shaped or club-like. The 
paraphyses are hyaline or coloured, sometimes forked. 

Mollisia Morthieri (Sacc.). The apothecia are developed on 
yellow spots of the lower epidermis of living leaves of Iivbvs 
Schleicheri and II. frvticosus. The young apothecia are reddish- 
brown and spherical ; when open they form yellowish-brown 
discs with very delicate margins. The asci contain eight 
spores, arranged in two rows. The spores are unicellular, club- 
shaped, and colourless. The paraphyses are colourless or 
brownish, with slightly bent points. 

Niptera. 

Apothecia as in Mollisia. The spores, however, on com- 
pleting their development are two-celled. 

Niptera hypogaea (Bres.). 1 Found by Bresadola in Southern 
Tyrol, underground on the roots of Adenostylcs albifrom. The 
apothecia are massed together on brown hyphae in blackened 
parts of the host-roots. The ascogenous disc is greyish-brown 
or whitish, with fine fibrous margins. The asci are spindle- 
shaped, and contain eight spindle-shaped colourless spores, 
which are at first one-celled, later two-celled. The septate 
colourless paraphyses are forked. 

Pseudopeziza. 

The members of this genus live as parasites in the leaf- 
tissue of higher plants and produce dead brown spots, in which 
the ascocarps are afterwards developed. The apothecia have 
delicate walls, and, after rupturing the epidermis, emerge 
as delicately-coloured saucer-like hymenial discs. The club- 
shaped asci contain eight spores, arranged in two rows. The 


Itrcsjvilola, Fungi trident, A. i.xxv., Fig. 1. 


PSEUDOPEZIZA. 


255 


spores are ovoid or elliptical, colourless, and unicellular. The 
colourless paraphyses have thickened apices, rarely forked. 

Pseudopeziza (Phacidium) trifolii (Bernh.). Leaf-spot 
disease of the clover. This disease appears on the leaves of 
various species of clover in Europe and America ; its attacks 
may attain considerable severity, and inflict great injury to 
crops. The leaves become spotted, and finally die off. The 
apotheeia occupy brownish-yellow discs on the surface of the 
leaf, and hence are not unlike pustules of a Puccinia. The asci 
are club-shaped, and contain eight ovoid, unicellular, colourless 
spores. The paraphyses have broadened apices, rarely forked. 
A conidial form (Sphaeronema phacidioides Desm.) is generally 
allocated to this species. 

Ps. trifolii (par. medicaginis) (Lib.) is found oil species of Medicago 

(Britain and U.S. America). 

Ps. bistortae (Lib.). This occurs on the lower epidermis of living leaves 
of Polygonum Bistorta, and P. viviparum, causing dark-brown swollen 
spots where the apotheeia are developed. Juel 1 has transferred this species 
to the Phacidiaceae, and named it Pseudorhytisma bistortae (D. C.). 

Ps. alismatis (Phil 1. et Trail) causes spots on leaves of Alisma Plantago 
(Britain). 

Fabraea. 

This genus is distinguished from Pseudopeziza by the spores, 
which, though at first unicellular, become two or four-celled. 
The species are parasitic in the leaf-tissue of higher plants. 

Fabraea astrantiae (Ces.). The mycelium lives in the leaf- 
parenchyma of Astrantia major and A. carniolica, causing dead 
spots. A form occurs on Sanicula europaea. 

F. ranunculi (Fries.) (Britain). The apotheeia of this are 
very common on brown spots on the leaves of various species 
of Panunmlus. 

F. cerastiorum (Wallr.) frequents leaves of Gerastivm (Britain). 

F. Rousseauana (Sacc. et Bomm.) occurs on leaves of Caltha palustris. 
(A British species if synonymous with Pseudopeziza calthae Mass.). 


Beloniella. 

The gregarious apotheeia are at first embedded, but break 
out later. Externally the apothecial discs are rough, dark brown, 

1 Mykol. Beitr. V ttensk. - A had . , 1894. 


256 


ASCOMYCETES. 


and striped, the margin being fibrous. The asci contain four 
to eight spores. The spores are generally ovoid or spindle- 
shaped, at first unicellular, but divided later into two to four 
cells by means of cross walls. The colourless paraphvses 
have thickened club-like apices. 

Belioi^ella Dehnii (Rabh.). 1 This parasite covers stems 
and leaves of Potentilla norvegica , and is distinguished by its 
sharp, spindle-shaped, bicellular spores. 

HELOTIEAE. 

The apothecia are generally quite superficial : less commonly 
they are at first embedded, and emerge later; or they may 
develop from a sclerotium. In form they are spherical, cup- 
shaped, or top-shaped, and a stalk of some kind is generally 
present. On opening, they form a cup or fiat plate, on which 
the hymenium lies exposed ; the cup is soft or waxy, and 
enclosed in a delicate wall, which is externally either smooth 
or hairy. The sporocarps consist of a pseudoprosenchyma 
(after Rehm). 


Sclerotinia. 

The sclerotia 2 give rise to smooth-stalked ascocarps with the 
form of beakers, funnels, or saucers. The stalks often produce 
rhizoids. The asci contain eight unicellular hyaline spores, 
elliptical or spindle-shaped, and of equal or unequal sizes. 
'Die paraphyses are thread-like. In several families conidia are 
formed before the sclerotia. Some forms are heteroecious. Most 
of the species are parasitic on plants. 

The Sclerotium diseases of the Vaccinieae. 3 

These are a well-known group of sclerotium diseases, and 
amongst them the following have been named as species. 

Sclerotinia vaccinii Wor. (Sc/. Unuda Weinm.). The 
sclerotium disease of the cowberry. The young shoots and 

'Figures in Hedwigia, I SSI . 

2 Literature: De Bary, “ Uehereinige Sclerotien u. Sclerotienkrankheiten,” 
Botan. Zeitung, 1886; also Jforphology and Biology of the Pungi, English edition. 

Brefeld, Srhimmelpi/ze. Heft. iv. u. x., and Botan. Zeitnng, 1876. 

Saccardo, Sylloge, Vol. vm. 

Woronin, M> in. del’acadetn. imptr. d. sci. d. St. Petersburg, vii. Ser. , t. 36, 18SS 
(with ten plates) ; also Bericlde <1. deutsch. botan. Ges., 1 804. 


SCLEROTINIA. 


257 


leaves of Vaccinium Vitis-Idaea exhibit in spring a mould- 
like coating, consisting of chains of lemon-shaped conidia. 

Woronin thus describes it : “ In the outer layers of the cortex, 
amongst the dying elements, a pseudoparenchymatous cushion is 
formed, from which simple or dichotomously branched hyphae 
grow out through the overlying cuticle. The individual members 
of the chains of conidia are separated from one another by a 
spindle-shaped piece of cellulose — ‘the disjunctor.’ ” 

The disjunctor spoken of here is a spindle-shaped cellulose 
body found between the single conidia ; it easily breaks across 
and so facilitates the breaking up of the chains of conidia 



A 


Fig. 135. — Sclerotinia vaccinii on Vaccinium Vitis-Idaea. Mummified Cowberries 
in fresh condition and in the following May, after development of Pezizc/.-cups. 
A, Chain uf conidia united by disjunctors. B , Germinating conidium after treat- 
ment with iodine ; the plasma has shrunk, but remains connected with the 
sporidia in process of abj unction. * (After Woronin.) 


(Fig. 135). It has its origin as follows: The conidia at first lie 
closely end to end, enclosed in a delicate primary membrane ; 
the partition-membranes split into two lamellae, each of which 
takes part in the formation of a cellulose body which gradually 
becomes spindle-shaped. In the course of its growth this cellulose 
body — the disjunctor — ruptures the primary enclosing membrane, 
and, being released, becomes more elongated, so that the conidia 
are pushed away from each other and fall apart. 

The conidia have a strong characteristic odour of almonds, 
attractive to insects, which carry off the conidia and dust them on 
the stigmata of other Vaccinium flowers. Wind is also, in all 
probability, an agent in the distribution of the conidia. The 


ASCOMYCETES. 


•258 

conidia germinate and give off long septate hyphae which, follow- 
ing the course of the pollen-tube, reach the ovary, and soon 
fill all four loculi with a white mycelium. The growth of this 
mycelium proceeds from the central axis towards the walls, and 
forms a hollow sphere open above and below. The diseased 
berries cannot be distinguished till ripe ; then, whereas the 
normal are red, the diseased are yellowish-brown to chestnut- 
coloured, and soon shrink up, leaving only the outline of the 
sclerotium. 

The dead or mummified berries fall prematurely, and lie over 
winter on the earth. In April or May, the sclerotia give rise 


A 



FlO. 130.— Belerotinia oxycocci on ^actinium Oxycoccv*. Young ahoot of Cran- 
berry with mature conidial cushion and diseased upper leaves. A , feiixa-cup 
developed from a sclerotial fmit : numerous rhizx)ids proceed from the l>aseof the 
stalk. B. Ascospores in stages of germination. C, Conidia in germination, with 
remains of disjunctors still attached. (After Woronin.) 


to several primordia or horn-like stalks, on the extremity of 
which an apothecium is afterwards formed. Rhizoids are pro- 
duced at the base of the stalk and attaching themselves to the 
ground act as supports and organs of nutrition. The apothecia 
contain both asei and paraphyses ; the latter are septate, dichoto- 
mously branched filaments, with club-shaped ends, and coated 
with a brown resinous substance. The asci have a canal at 
one end through which are ejaculated eight spores of almost 
equal size. These produce sporidia in water: in nutritive 
solutions, however, they form a septate mycelium with conidia. 
The ascospores bring about infection by means of one or two 
germ-tubes which penetrate the outer membranes of young 


SCLEROTINIA. 


259 


cowberry shoots, the stomata being always avoided. In less 
than three weeks conidia are produced. 

The mode in which the germ-tubes attack the host-plant is 
very remarkable. Woronin says : “ The germ-tubes developed 
from the ascospores grow inwards towards the vascular bundles 
of the host-plant and enter them ; then they continue to 
develop, but now in the opposite direction from the interior of 
the plant towards the periphery. Here a peculiar phenomenon is 
exhibited, the fungus exerts its in jurious effects on the surrounding 
tissues of the host-plant, then, having killed these, it utilizes 



Fig. 137. — Sclerotinia haccarum on Vo.cciniv.ru Myrtillus. Young shoot of Bilberry 
with deformed branch bearing white conidial patches on its lower side ; also a 
withered leaf. A, Conidial chains, and a portion enlarged. B , Shoot with an 
upper healthy ripe berry and a lower mummified one. C, P^zza-cup developed 
from a selerotium. i>, Ascospores ; the smaller incapable of germination, another 
germinating and giving off sporidia. (After Woronin.) 


them as food-material.” “ Finally, the germ-tubes penetrate 
between the elements of the outer rind already killed, and there 
develop to a stroma-like cushion of large-celled pseudo- 
parenchyma from which the chains of conidia emerge through 
the ruptured cuticle.” 

(Saccardo also mentions Scl. oreophila Sacc. on leaves of Vaccinium 
Yitis-Idaea.) 

Sclerotinia oxycocci Wor. The selerotium disease of the 
true cranberry ( Vaccinium Oxycoccus). The spores of this species 
are smaller than those of the preceding; each ascus contains four 


260 


ASCOMY CETES. 


larger and four smaller spores, the latter appearing to be rudi- 
mentary and incapable of germination. 

Scl. baccarum Schroet . 1 (Britain ). 2 The sclerotium disease of 
the bilberry ( Vacc. Myrtillus). This varies from the other species 
in having round conidia incapable of germinating in water, in 
having more robust apothecial beakers, and in lacking rhizoids. 
The spores are similar in number and arrangement to the 
preceding species. 

Scl. megalospora Wor. The sclerotium disease of the crow- 
berry {Erapdrum nigrum). This species is distinguished by the 


D 



Fir;. 138. — SrUrotinia mcgalo*/)ora on Vaceiniuhi uliqinotum. Partially withered 
leaf with a white conidial cushion on the mid rib. A , Conidial chains produced 
on a mycelium, resulting from an artificial culture of a**cospores in plum -solution. 
H, Isolated conidium with remains of disjunctors still attached. C , Twig with 
upper mummified berry. E, AscoHporcs ; one in its gelatinous envelope, the other 
giving off a germ-tube and sporidia. (After Woronin.) 


form of its conidia, and the manner of their germination ; in the 
form of the sclerotium, and the absence of primordia; in the 
absence of rhizoids; and, particularly, in having large ascospores 
almost similar to each other. 

The “white berries” of the Vacciniaceae are distinct from the 
mummified berries caused by Sclfrotinia . s 

Scl. aucupariae Ludvv. The mummified fruits of Pgrvs 
Aucuparia, resulting from this fungus, were first observed by 

1 Schroeter, Hedirii/ia, 1 879 ; Woronin {lor. rit.). 

- Sclerotia of this species have been found in Scotland hy Professor Traill. 

‘Magnus and Ascherson, Berichte <1. deufxrh. botan. Gtx,, 1S89: also Zoo !. - 
botan. (Its. , Vienna, 1S91. 


SCLEROTINIA. 


261 


Woronin 1 in Finland, and later by Ludwig in the Erz mountains. 
The ascocarp developed from the sclerotia has no rhizoids. The 
ascospores infect leaves, and there the conidia are produced. 

Scl. padi Wor. Causes mummification of the fruits of 
Prunus Padus. Woronin regards Monilia Linhartiana Sacc. as 
belonging to this Sclerotinia. 

W oronin also considers the conidial form Monilia cinerea 
as related to the mummified fruits of cherry. 

Ovularia nelans on Mespilus is probably also a form of some Sclerotinia. 

A Sclerotinia occurring on Cotoneaster nigra produces mummification of 
the fruit, and forms conidia on the surface. 

Monilia fructigena of the apple, pear, quince, plum, peach, etc., is in 
all likelihood a form of some Sclerotinia, although the ascus-form is still 
unknown (see also “ Fungi imperfecti ”). 

Scl. betulae Wor. (U.S. America). This sclerotium of the 
birch-fruit was discovered by and briefly described by Woronin 
in 1888. Nawaschin 2 has recently re-investigated it, and 
named it the “ birch-catkin disease.” It is found on the green 
catkins in June. The fruits containing sclerotia are obcordate 
in shape, instead of the normal elliptical form with both ends 
acute ; the wings are similar to those of healthy seeds. The 
sclerotium is composed of a very hard white pseudoparenchyma, 
which passes in the form of a horse-shoe round one side of the 
apex of the fruit (Fig. 139). The outer layer is black and very 
firm. Sclerotia placed on moist sand produced ascocarps at the 
beginning of May. Development in the open also takes place 
about this time. In the birch forests near St. Petersburg this 
disease is common, and birch-catkins containing sclerotia may 
be found abundantly amongst fallen leaves about the month of 
May. From each sclerotium there are produced one or two 
ascocarps, with rhizoids and stalks of a length varying with 
the depth of dead leaves on the ground. The apothecia 
are at first funnel-shaped, but later became saucer-shaped 
and l-lmm. broad, with a golden or fleshy colour. The asci 
contain eight spores which are forcibly ejaculated, and if a 
handful of damp birch leaf-mould is thrown up into the air 

1 Woronin, Berichte cl. deutsch. hotan. Ges., 1891; also Mem. de Vacacl. imp. 
d. sci. de St. Petersburg, 1895. With five plates. 

2 Nawaschin, Sclerotinia betulae, Wor. Russian brochure with four coloured 
plates, 1893. 


262 


ASCOMYCETES. 


a cloud of spores so ejected may easily be seen. Infection 
takes place on the birch flowers. It is possible to promote 
germination in water and on moistened leaves, but the germ- 
tubes soon die. 

This disease, on account of the small size of the birch fruit 
and the tiny sclerotia, remained for a long time quite un- 
observed, yet it seems to be common everywhere ; in Russia it 
has been found frequently, also in Germany, North America, 
and Japan. It possesses considerable economic importance, 
since diseased seeds are no longer capable of germination. 



Flo. 139. —ScUrotinia bctulae. «, Birch fruits with sclerotia, which have 
germinated and formed cup-like apothecial discs ; rlmoids have developed on 
the stalks. It, Birch fruit, somewhat enlarged, with semilunar sclerotia. (After 
Xawaschin.) 

Hormomyia betulae Wtz. often occurs along with the above. 
It causes the production of thick spherical fruits with little or 
no wing. ScUrotinia adusta Karst, has also been found on 
birch leaves in Finland. 

Scl. alni Naw. Woronin found this first on catkins of 
Alnus incana. Xawaschin has more recently investigated it. 1 

Scl. rhododendri Fischer. 2 This was first discovered by 
Fischer in 1801 in fruits of the Alpine-rose ( Rhododnidron 
ferrugineum and R. hirsutum ) in Switzerland. It has since 
been observed in various parts of Switzerland and the Tyrol. 

1 Nawaschin, Berichte d. dentsrh. Man. 0(»., 1894; Maul, Htdtcujia, 18!M, 
p. 213. With two plates. 

2 E. Fischer, Naturf orach, (ten. Bern, 1891 ; also Berichte <1. schtctiz. hold n. Ges., 
1894. With figures. 


SCLEROTINIA. 


263 


Fischer succeeded in obtaining stalked ascocarps from sclerotia 
of one and two years old. They resembled most closely those 
of Scl. vaccinii, their stalk being provided with numerous rhiz- 
oids. The asci contain eight similar spores which germinate 
directly on ejaculation. They develop a mycelium and, later, 
chains of chlamydospores which separate by means of disjunctors. 
The little conidia found by Woronin on Vaccinium are never 
produced. The paraphyses are generally unbranched and corre- 
spond in length to the asci. 

The mummified fruits are easiest found after the healthy 
capsules have dehisced, then the diseased ones remain closed. 
In winter the healthy capsules remain attached to the plant, 
the diseased fall off. Seeds of diseased capsules are completely 
overgrown by hyphae. 

Wahrlich 1 found sclerotia in capsules of lih od. dahuricum 
from Siberia. They gave off a sclerotial ascocarp with a stalk 
devoid of rhizoids. The mummified fruits resemble closely those 
of Scl. rhododcndri. 

Scl. heteroica Wor. et Naw. = Scl. ledi Naw . 2 occurs on 
Ledum palustre in Russia and Finland. It is very similar to 
Scl. rhododendri, but is distinguished by the paraphyses being- 
swollen and frequently forked at the end. In nutritive gelatine 
a copious mycelium is developed, and produces chains of ripe 
conidia with tiny disjunctors. Woronin found that these conidia 
are produced only on Vaccinium uliginosum, never on Ledum ; 
but the conidia so formed can successfully infect the ovary of 
Ledum. We have here the first known case of heteroecism 
outside the Uredineae. 

Scl. sclerotiorum Lib . 3 (Britain and U.S. America). The 
sclerotia of this fungus are found in many various plants. 
They fall to the ground with the dead plants, hibernate under 
snow, and on the arrival of warmer weather in spring give 
rise to several stalked apothecia. The ascospores are ejaculated 
from the asci, germinate, and produce a parasitic mycelium, 
described thus by De Bary : “ The ripe spores of Peziza 

sclerotiorum produce germ -tubes on any moist substratum. 

1 Berichte d. deutsch. botan. Ges., 1892. 

2 Nawasehin, Berichte d. deutsch. botan. Ges., 1894, p. 117. 

3 Brefeld, Schimmelpilze, iv. and x. ; De Bary, Morphology and Biology of the 
Fungi ; and Botan. Zeitung , 1886. 


264 


ASCOMYCETES. 


These develop to strong mycelial threads if they reach any 
source of nutriment, such as disorganized bodies and particularly 
dead plants. On any other substratum the germ-tubes never 
pass beyond a rudimentary stage. The germ-tubes developed 
in water cannot make their way into living plants. If, however, 
grown in suitable nutriment, the mycelial threads are smaller 
and capable of penetrating as parasites into suitable hosts. This 
they are able to do because they give off a fluid which enters 
into and kills living plants. The dead parts of the plants 
serve as nutriment to the fungus, which makes its way into 
the tissues and causes death of cells in direct contact or im- 
mediate neighbourhood. The deadly fluid separated by the 
fungus contains, as an essential constituent, an enzyme soluble 
in acid solutions and capable of dissolving the cell- walls ; also 
a number of imperfectly known organic and inorganic acids 
and salts, amongst which oxalates can certainly be proved. 
The mycelium generally penetrates parts covered only by cuticle 
or a thin periderm. It does so by hyphal branches which grow 
into the air till they reach some suitable host ; then, stimulated 
by the pressure, they give off characteristic organs of attachment, 
which secrete a cell-killing fluid and cause disorganization of 
the place attacked ; they derive nourishment from the products, 
and give off branches which penetrate into the plant.” 

Conidia capable of germination are never produced, though 
rarely tiny spermatia or conidia incapable of germination are 
abjointed from the mycelium. 

A Botrytii- stage is certainly never present in the life of 
this species. 

Scl. sclerotiorum is one of the worst enemies of cultivated plants. 
l)e Bary observed total or partial death resulting from it to 
the following plants : Phaseolus vulgar is, Pvtunia nyctayiniflora 
and P. violacrae, Solanum tuberosum, Zinnia rlrgans, Hcfiant/ius 
tubcrosvs, and Daucus Carota. It has also been found on species 
of Brassica, Beta, Cichorium, Dahlia, Topinambur, etc., and on 
seedlings of numerous other dicotyledons. It is thus evident 
that many and varied plants, belonging to widely removed 
families, may serve as hosts ; on the other hand the fungus 
avoids certain plants, and is known to injure species in one 
locality, which it avoids in another. 

De Bary regards a destructive canker on hemp in Russia 


SCLEROTINIA. 


265 


( Peziza Kauffmaniana Tichoin .) 1 as related to, or identical with 
Scl. sclerotiorum . Behrens, however, is inclined to ascribe it 
to Scl. FucJceliana, which has occasionally a Botrytis- stage. This 
hemp disease has also been found in Alsace .' 2 

Humphrey 3 regards this species as the cause of a disease 
of indoor cucumbers ; he ascribes a Botrytis- stage to it. 

Scl. sclerotiorum is best known by the conical funnel-shaped 
depression in the hymenial disc, not present in other species. 

Sclerotinia trifoliorum Eriks 4 (U.S. America ). 5 Clover 
is not attacked by the Sclerotinia last considered, but falls an 
easy prey to this species, which again derives but scanty nourish- 
ment from such food as fresh carrots. Scl. trifoliorum is 
observed wild only on species of clover, and is there fairly 
common ; many other plants, however, have been artificially 
infected by it. Host-plants are attacked through their green 
foliage, which very soon becomes brown and shrivels up. If 
the atmosphere be sufficiently moist, the mycelium emerges 
on the exterior and spreads to neighbouring organs or plants. 
Sclerotia are not often formed superficially as with Scl. 
sclerotiorum, because the mycelium lives principally inside 
the plant tissues. This mycelium resembles that of Scl. 
sclerotiorum in its peculiar property, that successful infection 
only follows if the fungus has lived for a time saprophyticallv : 
on this account direct infection by spores is harmless. In the 
secretion of an enzyme and of oxalic acid, and in the manner 
in which it destroys the tissues of its host-plant, this species 
behaves like Scl. sclerotiorum just described. It is distinguished 
by its larger ascospores, and the absence of a central funnel- 
shaped depression in the hymenium. Spores germinated in water 
produce numerous bodies (so-called spermatia) which distinguish 
the species from Scl. FucJceliana where this does not take place. 

Rostrup G found in Denmark that Medicago lupulina suffered 

1 Tichomiroff, Bull. soc. nat. de Moscou, 1868. 

2 Behrens, “Ueber das Auftreten d. Hanfkrebses im Elsass.” Zeitschrift f. 
Pflanzenkrankheiten, 1891, p. 208; “ Troekene u. nasse Faule d. Tabaks,” idem, 

1893, p. 82. 

3 Humphrey, Arjric. exper. station Mass., 1892, pp. 212-224. 

4 Kuhn, “Die Sklerotienkrankheiten d. Klees.” Hedwigia, 1870. 

Rehm., Entwickehmgsgesch. eines d. Klee zerstorenden Pilzes. 

5 Massee (British Fungus-flora, iv. , 1895). “There is no evidence of this species 
having occurred in Britain.” 

6 Rostrup, Tidsskrift for Landokonomie, 1890. 


266 


ASCOMYCETES. 


most from this fungus ; red clover was less affected, though 
the disease often had its origin in that species ; while white 
clover was least often attacked. He recommends keeping out 
jl leclicago from clover mixtures, and the addition of a large 
proportion of grass-seeds. Fields badly affected should be 
kept out of clover-cultivation for several years. English and 
French white clovers he found to be very sensitive, but distri- 
bution of the fungus did not take place by means of seed. 

Scl. tuberosa (Hedw.) (Britain and U.S. America). This 
on the rhizomes of Anemone nemorosa causes formation of 
sclerotia larger than filbert-nuts. The ascospores on germination 
produce groups of flask-shaped processes from which are given 
off chains of spherical conidia incapable of germination. Certain 
pycnidia which appear on the anemone-plants or on the sclerotia 
belong to a parasite ( Pycnis sclerotivora Brefeld). 

Scl. bulborum Wakk . 1 (Britain). Wakker observed this form 
on hyacinth, onion, etc. It is very similar to Scl. trifoliorum, 
but the hyacinth-fungus will not infect clover, and vice versa. 
The leaves attacked become rotten and the plants die . 2 * * 

Eriksson describes, from Wermland (Sweden), a destructive appearance of 
bulb-rot due to sclerotia, which he attributed to Scl. FitckeHana De Bary. 

Scl. candolleana Lev. on oak-leaves. 


Appendix. 

Sclerotia of Unknown Affinity. 

Scl. oryzae Catt. Bice plants ( Oryza saliva) are often 
attacked by this Sclerotium, and a disease called “ Brusone ” 
produced. The sclerotia are found during June in the sheaths 
and stems. The symptoms are blackening at the base of plants 
and withering of upper parts. 

Scl. rhizoides Auersw. occurs on living plants of Pfialaris 
arv ndinacca, and Calamagrostis ; also on dead leaves of Dactylis 
fjlomerata. 

Scl. rhinanthi Magn . 8 forms sclerotia on the roots and root- 

1 Wakker, Allgem. Vereenig. roor B/ocniholh ncultnr, 1SS3-84 ; also llotan. 
Centra/lilatt, XXIX., 1SS7. 

2 G. Massee (Gardener' s Chronicle, Yol. xvi., 1 S!H ) gives description and 

figures. 

;i V erhand. d. hot an. Ver. <1. Pror. Brandenburg, xxxv. 1804. 


SCLEROTIA OF UNKNOWN AFFINITY. 


267 


neck of living Rliinanthus minor ; these bodies begin their 
development in the cambium and bark, which they kill ; after- 
wards the wood itself may be attacked. 

Sclerotinia with Botrytis-conidia . 1 

Scl. Fuckeliana De Bary. This Sclerotinia is distinguished 
from all preceding ones by its passing through a Botrytis- 
conidia stage ( Botrytis cinerea ). If conidia are sown out on 
plum-juice gelatine, there appear within fourteen to twenty-one 
days round groups of sclerotia, which soon 
give rise to conidia. From such artificially- 
reared sclerotia I have never succeeded in 
getting the Peziza- fruit, so easily cultivated 
from sclerotia gathered in the open-air ( e.y . 
from vine leaves). 2 Thus the actual proof 
that Scl. Fuckeliana and Botrytis cinerea are 
stages in the life of the same fungus is not 
reached by this experiment. 3 The two forms 
are, however, very frequently met together. 

The sclerotia of Scl. Fuckeliana are produced in the mesophyll 
of the leaves, also in the parenchyma and epidermis of the 
host-plants, but never in the wood. Peziza- fruits with flat 
apothecia are produced from them. Sclerotia are found in vine 
leaves and over-ripe grapes (Fig. 140), especially of the Biesling, 
Orleans, and Sylvaner varieties. 4 Other plants and fruits may 
also be attacked. Diseased parts become brown from the 
effects of the parasitic mycelium, and die off. The mycelium 
can only live parasitic after it has been strengthened by a pre- 
vious saprophytic existence. Ascospores are thus unable to 
effect direct infection. The Botrytis- conidia seem, however, 
capable of directly infecting a host-plant, at least I have always 
succeeded in infecting Conifers successfully with the conidial 
form Botrytis Douylasii. 

’See also Botrytis amongst the “Fungi imperfecti.” 

2 Brefeltl, Heft iv. , p. 1*29, and x. , p. 31o; Tubeuf, Beitrdge z. Kenntniss d. 
Baumkrankheiten, 18S8. 

3 Zopf. (Die Pilze, p. 742) states that Pesiza-fruits may be reared from these 
sclerotia after they have rested a year. 

4 Muller-Thurgau, “Die Edelfaule d. Trauben. ” Landwirth. Jahrbuch, 1888 
(Ref. in Botan. Centralblatt, xxxv., 1888, p. 94). 



Fig. 140 . — Sclerotinia 
Fuckeliana. Ripe-rot of 
the Grape. Berry with 
sclerotia. (v. Tubeuf 
del.) 


268 


ASCOMYCETES. 


Epidemics of great magnitude have been ascribed to attacks 
by the Botrytis - forms of this Sclerotinia. Thus on lilies in 
England , 1 on yellow gentian , 2 on male flowers of Conifers, and 
on the twigs of Conifers and other plants. This is especially 
the case in houses under glass, where the fungus, favoured by 
the moist atmosphere, lives as a saprophyte on dead plant-remains, 
and multiplies till it becomes strong enough to act as a 
parasite. It is, however, quite possible that conidial forms of 
other sclerotia (e.g. Scl. sclerotiorum ) may be confounded with 
this species. 



Fio. 141. — Botrytis cinerea (Set. h uclcetiana ). Brunch of Primus triloba with two 
diseased shoots, withered and dead. (r. Tubeuf phot.) 

The presence of Botrytis and allied forms on the vine is the 
cause of a disease of great economic importance, because severe 
loss may be incurred through rotting of the grapes and the 
injurious after-effects on the “most.” 

A decay of the potato-plant is said to be caused by sclerotia 
formed inside the stems, and also by a Botrytis . 8 Smith 4 has 
figured similar sclerotia, which lie ascribes to Pc ; iza jmtuma 
Berk, and Wil. 

1 H. M. Ward, Anna/* of Botany , 1SSS. 

- Kissling, Hedwiyia, 1889. 

* Ritzema-Bos., Zeit*rh. f Pjianz< nkra nkht io n , 1894; O. Kirchner, M'urtemlmiy. 
Woch' iib/att f. Landirirth., 1893. 

4 Worthington (L Smith, Ditcasif i of Fold and <!ard<n Crop ■«. London, 1884. 


SCliEROTINIA WITH BOTRYTIS-CONIDIA. 


269 



Sclerotia, along with Botrytis- conidia, have been found fre- 
quently on diseased geraniums. 

During the summer of 1894 a withering of twigs of Prunus 
triloba occurred in several gardens at Munich (Fig. 141). A 
mycelium was found in the bark, leaf-petioles, and young 
ovaries, while Botrytis-coniditi were 
developed on the dead parts. 

With these I successfully infected 
young needles and twigs of spruce. 

Sclerotia were also formed on plum- 
gelatine in fourteen days. The 
parasite in this case had killed old 
twigs of Prunus, and also infected 
twigs of Conifers. 

Botrytis Douglasii is a parasite 
which 1 studied some time ago on 
account of its presence along with 
a disease on the Douglas fir ( Pseu - 
dotsuga Douglasii). 1 I have since 
had reason to believe that it is 
allied to some form of sclerotium 
like that just considered, and my 
view is supported by Behrens. 2 
The disease as seen in various 
parts of Germany is characterized 
by withering, curling-up, and death 
of young shoots towards the sum- 
mits of voung seedlings, and on the 
lower twigs of older trees up to 
about five feet above the ground. 

In autumn, black sclerotia about 
the size of pin heads, break through 
the epidermis under the old bud- 
scales, at the base of dead shoots, 
and on the needles. In addition 
tangled hyphae are also formed, 
in a moist chamber, tufts of erect conidiophores arise, and 
branch, forming numerous whorls of conidiophores, from which 


Fig. 142.— Botrytis Douglasii on the 
Douglas Fir. The young shoots and 
apex of last year’s shoot are dead. 
(After Tubeuf.) 


to these, smaller masses of 
When sclerotia are placed 


1 v. Tubeuf, Beitra/je z. Kenntniss d. Baumkran kheiten, Berlin, 1888. 

2 Behrens, Zeitsch. f. Pflanzenkrankheitzn, 1895. 


270 


ASCOMY CETES. 


oval hyaline conidia are abjointed. These germinate at 
once in water, and infect young developing shoots or needles 
of Douglas fir, silver fir, spruce, and larch. Death of these 
ensues in a few days, and finally the whole plant is killed. 
On the dead needles a copious development of Botrytis takes 
place, and the conidia being easily detached, spread the 
disease in damp localities. The mycelium and conidiophores 
are very sensitive to drought. The sclerotia serve to carry 
the fungus over winter, and may be found in autumn and 
winter. 

I have found Juniperis communis with its young shoots dead, 
and sclerotia similar to the above on the needles. 

Whether Sderotinia Kerneri Wettst. found on needles of Abies pectinate 
is parasitic or not, I do not know. 

Scl. galanthi Ludw. 1 Ludwig observed this disease on 
snowdrops. In place of the flower a shapeless mass was pro- 
duced, completely covered with conidiophores of Botrytis. The 
sclerotia develop inside the tuber. 

Scl. pseudotuberosa (Kehrn). (Sri. Batschiano Zopf or Ciboria 
pseudotuberosa Rehni) (Britain). The cotyledons of acorns are 
sometimes found replaced by a firm sclerotium, from which a 
peziza-fruit ( Ciboria ) is produced. Nothing is known in regard 
to mode of infection or the parasitism of this species. 

EU-PEZIZEAE. 

The apothecia, at first closed, open out to form saucer- 
shaped or cup-like discs, with a margin. The discs have 
usually a thick hypothecium ; they are fleshy or waxy in 
texture, and are often brightly coloured. 

Dasyscypha. 

The waxy or membranous ascocarps are sessile or shortly 
stalked, and beset on the outer surface and margin with hairs 
of various colours. The asci dehisce by a round apical opening. 
The spores are ellipsoidal or spindle-shaped, unicellular, and 
hyaline. The paraphyses are thread-like. Most of the forms 
are saprophytic on dead plants; the following species alone 
is known to be parasitic. 

1 Ludwig, Lehrbuch <1. niedtren Krypioijamen. 


DASYSCYPHA. 


271 


Dasyscypha (Peziza) Willkommii, Hartig. 1 The Larch Canker 
(Britain and U.S. America). Everywhere in the mountains, the 
home of the larch, one finds, on young branches and old stems, 
depressed canker-spots, on which the sporocarps of Dasyscypha 
Willkommii are developed. Young twigs, when attacked, are 
already conspicuous in July and August by their pale and 
withered needles, and on them small 
canker-spots will be found ; these rapidly 
enlarge so that on older stems they may 
reach very great dimensions. Hartig easily 
succeeded in producing canker-spots on 
healthy trees by artificial infection. 

If canker-spots are examined soon after 
the death of the bark, the stromata will 
be found as yellowish- white pustules. 

Conidia are produced either on the free 
surface or in the internal cavities of a 
stroma ; they are tiny unicellular hyaline 
bodies, produced from little conidiophores. 

Hartig never succeeded in getting these 
spores to germinate. If the atmosphere 
be moist enough the apothecia make their 
appearance later on the same places ; they 
are externally yellow, and internally orange- 

. . " ill- -i Willkommii. Three asci and 

coloured. the apothecia! disc carries long two paraphyses isolated 

. it, , i i- , • i • from an apothecium. (After 

thread-like paraphyses and cylindrical asci r. Hartig.) 
with rounded apices (Fig. 143). The asco- 

spores are oval, unicellular, and hyaline. They germinate and 
give off one or two germ- tubes which are unable to penetrate 
the periderm of a host-plant, and only find entrance through 
wounded places. Wounds are very common on larch as the 
result of hail, or injury to twigs by snow or ice, or destruction of 
needles by insects. For example, the Larch-moth ( Coleophora 
laricella) is well known to cause less damage on the mountains 
than in the lower regions, and in the same degree Dasyscypha is 
least injurious to mountain forests. 

The mycelium is septate and much branched ; it spreads 
chiefly through the soft bast, especially in the sieve-tubes and 

1 R. Hartig, (Jntersuch. aus d. forstbotan. Institut Mtinchen, i., 1880. M. Will - 
komm, Mibroa. Feinde des Waldes, n., 1868. 



Fig. 143. — Dasyscypha 


272 


ASCOMYCETES. 


intercellular spaces, but it may also penetrate the wood as far 
as the pith. The fungus only spreads during autumn and 
winter, never during summer, the vegetative period of the 
larch. The attacked tissues of the bark turn brown and shrivel 
up, causing the depressed canker-spots. Healthy parts continue 
their growth normally, and are frequently cut otf from diseased 
areas by formation of layers of secondary cork ; this isolation 
is, however, rarely effective, since fresh invasions of mycelium 
from the wood into the bast take place annually, and thereby 
the canker-spots keep enlarging for an indefinite time. 

The fungus develops reproductive organs only in damp marshy 
situations. On this account spore- formation is less frequent on 
mountainous slopes than in moist valleys and ravines. The 
larch, on its first introduction into the low-lying parts of Germany, 
Denmark, and England, was much cultivated as a pure forest in 
close damp localities, and with great success ; but now this parasite 
has followed its host from the mountains and causes ever 
increasing damage. 

As preventive measures may be recommended : larches in 
low-lying districts should be grown in open, airy situations, and 
never massed together nor placed in the neighbourhood of diseased 
larches. 

Lachnella. 

The reproductive organs are similar to Dasyscypha, but the 
apothecia are firmer and generally have no stalk ; the spores as 
a rule become two-celled at maturity. 

Lachnella pini Brunch. 1 occurs in Norway on twigs of Pinvs 
sylvestris, as a parasite which quickly kills young plants and twigs. 
It is rare on old plants. The apothecia resemble those of 1). 
IVillkommii, but are larger, externally brown, and covered with 
brown hairs and scales. The disc is reddish-yellow with a whitish 
margin. The asci measure about 100/u by 9 m, and contain 
colourless unicellular spores about 20/u long. 

Rhizina. 

This genus contains the single species Rhizina undulata 

1 Brunchorst, Xogle nor/»k< skorsygdomme, Bergens Mus., IS92. 

2 Rhizina has a position somewhere between the I’tzizeac ami the llelvtllear. 
•Saccardo places the genus under Pczizeac, while Schroeter makes for it the 
special group of Rhiztnar.ei, included under his /lelvtllinti. 


RHIZINA. 


273 


Fr. ( Ilk. infiata, Schaeff.). Root fungus, or Ring-disease. fins 
fungus is found as a saprophyte on the earth, especially where 
forest fires have occurred ; also as a parasite on indigenous and 
exotic conifers. As such it has been observed in nurseries in 
various parts of Germany, and in woods of Pmus Pinaster in 
France. The fungus itself is known in Britain, though not as 
a parasite. 



Fig. 145. — Section of hymenium. a, Para- 
physes; b, secreting-tubes ; c, asci, each wit 1 
eight spores. (After Hartig.) 


Fig. 144 . — Sporophores of Rhizina undulata. 
■a, Upper surface ; b, lower surface ; c, small 
sporophores. (After Hartig.) 



The disease extends from a centre and attacks one plant 
after another, causing them to lose their needles and die. 
The sporophores are large (f to 2 inches), chestnut-biown, 
flattened or undulating structures, which sit directly on the 
mycelium, without a stalk. On the upper surface is the 
ascogenous layer which, when moist, is peculiarly stick} anc. 

1 R. Hartig. Forstl-naturwissen. Zeitschrift. , 1892, p. 591; Piillieux, Compt. 
rend, de la Soc. des Aijric., 1880. 


274 


ASCOM YCETKS. 


glutinous ; it consists of small eight-spored asci over which 
project septate paraphyses, and also non-septate paraphyse-like 
structures which discharge a brown secretion. The ascospores are 
unicellular, hyaline, and canoe-shaped ; on germination they give 
off' a germ-tube which immediately develops into a septate 
mycelium. The mycelium is found in the intercellular spaces 
of the rind-parenchyma, but in the bast it grows both inside the 
cells and between them, so that the sieve-tubes are often completely 




Fig. 140. — Rcnt-aystcm of a Silver Fir 
overgrown and killed by the mycelium of 
Rhizina undulala. (After Hartig.) 


Flo. 147. — Asconporcn of Rhitincu o, As 
taken from the aacus ; /», *24 hours after 
sowing ; r, 4S hours after sowing ; rf, the 
spore of c enlarged. (After llartig.) 


filled up. Masses of fungoid pseudoparenchyma are frequently 
formed between the dead and diseased tissues. Strands of the 
nature of Iihizoctania, emerge from the diseased roots, many 
of them carrying thread-like processes, at the extremity of 
which an oil-drop is secreted and escapes on rupture of the apex. 

According to Hartig, very tiny conidia are abjointed from 
the mycelium. 

He la Boulage 1 and l’rillieux have both come to the conclusion 
that “la maladie du rond ” of J'inus .v/hrsfris and P. maritnnn 
is the same disease as the “ring-disease” caused by lihizino. 

1 li ill I. <!' In soc. <h * .1 f/rir. <h Fmnce, 1SS0. 


THE HELVELLACEAE. 


-I 5 


Appendix. 

The Helvellaceae. 

This family is well known, some as poisonous, others as 
edible fungi (morel, etc.), and a few are suspected of being para- 
sites. The ascogenous layer occupies the upper surface of the 
sporophores, which grow on the earth and assume many various 
forms. As a rule they are erect and fleshy, and more or less 
lobed, wrinkled, or folded. 

USTILAGINEAE. 

The Ustilagineae or Smut-fungi are distinguished by their 
dark-coloured or black ehlamydospores, which, on germination, 
produce some form of promycelium capable of giving rise to 
an indefinite number of conidia or sporidia . 1 The ehlamydospores 
themselves are produced in large numbers from a mycelium, 
and serve as resting-spores to carry the fungus through the 
winter, being often, in fact, the only part which persists. An 
endogenous formation of spores in sporangia as in the lower 
fungi, or in asci as in the Ascomycetes, does not occur in 
the Ustilagineae, Uredineae, or Basidiomycetes. 

The resting-spores of the Ustilagineae contain only one 
nucleus, the result of copulation of two nuclei ; their formation 
thus marks the end of one generation, and their germination 
the beginning of a new. In the case of the Uredineae, Basidio- 
mycetes, and Ascomycetes, the beginning of the new generation 
is indicated by the germination of the teleutospore, the formation 
of basidiospores on the basidium, and the germination of the 
ascospore respectively. 

All the Ustilagineae are parasitic on higher plants, the 
mycelium growing intercellularly and nourished by means of 
haustoria sunk into the host-cells. The mycelium itself causes 
neither disease nor deformation of plants, and it is only when 

1 Brefeld regards the promycelium of the Ustilagineae not, like De Barv, as 
a mycelial structure, but as a conidiophore or basidial structure. In accordance 
with this view he has founded his intermediate group, the Hemibasidii corre- 
sponding to the Ustilagineae. Brefeld then subdivides this group into (a) Ustila- 
gineae (Ustilago, Sphace/otheca, Schizonella, Tolyposporium), which as a rule 
have a septate promycelium ; and (b) Tilletieae ( Tilletia, Entyloma , Melanotaenium, 
Schroeteria, Thecaphora, Sorosporium ), with non-septate promycelia. (Schimmef - 
pilze, Heft v., 1883, and Heft xi., 1895.) 


276 


USTILAGINEAE. 


the resting-spores are developed that deformation occurs. These 
spores arise by intercalary growth in the mycelium, which is 
generally completely used up in their formation ; they are 
produced in large numbers, and scattered after decay of the 
tissues enclosing them. 

As a result of the germination of the resting-spores, there 
is produced either a mycelium capable of immediate infection, 
or a promycelium from which conidia 1 are abjointed. In the 
latter case, conidia are generally formed in succession, and 
continue to be given off from the promycelium for a considerable 
time. They either give out a germ-tube capable of infecting a 
new host, or give rise to further conidia. The latter process 
is most frequently observed in artificial nutritive solutions, 
where the conidia continue to sprout in a yeast-like manner 
till nourishment is exhausted, when they germinate and form 
mycelial filaments. In the host-plant, chlamydospores alone 
are developed, conidia exceptionally ( Tuburcinia and Enty- 
lomd). 

The Ustilagineae are very dangerous and injurious enemies 
of cultivated plants, especially to the various cereal crops. The 
species are fairly easy to identify, because each is, as a rule, 
confined to one or a few species of host. The smut-fungi are 
best combated by sterilizing the seed of suspected cereals in 
a copper sulphate solution or in hot water shortly before 
sowing out; (see General l’art, chap, vi.) In this way any 
adherent smut-spores are killed, and where this preventive 
measure is regularly carried out, disease is less common and 
its effects considerably minimized. 

The Ustilagineae include the following genera : Uxtiiago, 
Sphacelotheca, Schixonella, Tolyposporium, Tillctia, Entyloma, 
Melanotaenium, Urocystis, Tiiburcinin, Daossansia, Schroitcrin, 
Theeaphora, Sorosporium, Graphiola, Schinzia, Tubnrnlaria. 

Ustilago. 

The vegetative mycelium makes its way through the tissues 
of the host-plant without causing any deformation. The spores 
are developed in certain parts of the host, and form a much- 
branched, compact, sporogenous mycelium, with membranes 


1 ‘ Conidia ’ = the sporiclia of Dc ltary. 


USTILAGO. 


277 



which at first swell up in a gelatinous manner. Spores are 
formed inside the ultimate ramifications of the mycelium, and 
as they reach maturity, the membrane loses its gelatinous 
character, the cells break up, and the spores are set free; they 
are dispersed as a dry dusty powder after rupture of the tissues 


Fig. 148 . — Ustilago maydis. Tlie head has been exposed to view by dissecting 
away the enclosing leaves ; it is beset towards the apex by smut-bous. 

(v. Tubeuf phot.) 

of the host enclosing them. The spores germinate, giving rise 
to a promycelium (basidium), which becomes divided up by 
means of cross-septa into several cells, from each of which 
conidia are laterally abjointed. These conidia sprout yeast- 
like, and give off new conidia, or they produce a mycelium ; 


278 


USTILAGINEAE. 


the former is the case when nutrition is abundant, as when 
under artificial cultivation, the latter under less favourable 
nutrition ; in very unsuitable conditions, the constituent cells 



Fin, Hi \—U»tila<io mai/dit. Diseased Maize-heads after removal of enclosing 
leaves. The heads' are beset with smut-boils of all sizes, some ruptured, others 
still unbroken, (v. Tubcuf phot.) 


of the promycelium may each develop directly into hyphae 
capable of infecting a new host. 


USTILAGO. 


279 


Ustilago maydis (D.C.) 1 (Britain and U.S. America). 2 This 
smut of Zcct Metis produces large and conspicuous deformations 



on leaves, leaf-sheaths, stems, roots, and all parts of the male and 
female flowers. These are whitish, 
gall-like swellings and blisters, 
containing a mass of gelatinous 
mycelium, from which spores are 
produced. The swellings may 
attain to the size of a fist, or 
even larger. The spores appear 
at first as dark olive-green 
masses seen through the lighter- 
green outer tissues of the host- 
plant. When mature the spore 
masses cause rupture of the 
enclosing host-tissues, and escape 
as a dusty powder. The spores 
are dark-brown in colour, irre°u- 
larly spherical in shape, covered 
with delicate spines, and measure 
9-1 in diameter. They re- 
main capable of germination for 
many years. 

On being sown from the host- 
plant directly into water, very 
few spores germinate at once, 
yet if sown in the following 
spring they readily do so. In a 
nutritive solution ( e.g . plum-juice 
gelatine) an abundant germina- 
tion may be obtained at any 
time. A delicate hyaline hypha 
is given out first, and after be- 
coming divided up by several cross-septa, it proceeds to abjoint 
conidia from various places. The conidia sprout in the gelatine 


Fig. 150. — Ustilago maydis in head of 
Maize, (v. Tnbeuf phot.) 


1 American Literature: U.S. Dept, of Agriculture. Report , 18S9, p. 380, with 
description and recommendations as to treatment. Also Ohio A aric. Exper. Stat 
Bulletin, \ ol. m., p. 271, 1890. 

- I lie principal authorities for the occurrence of the Ustilagineae in Britain 
and the tinted States are Plowright ( British Ustilagineae, 1889), and Farlow 
and Seymour (Host-index of Fungi of U.S. America, . 1891). (Edit.) 


•280 


U STI LAG I N EA K. 


in a yeast-like manner, lmt on exhaustion of the nutritive 
materials, the primary conidia, and even the constituent cells 
of the promycelium, give off germ-tubes. Conidia are never 
found on the maize-plant itself, but Brefeld’s investigations 
have demonstrated their production on dung-cultures, so that 
conidia may possibly be produced on manure-heaps or manured 
soil, and young plants be infected by them. Ilrefeld has, 
by means of germinating conidia, successfully infected maize- 



r 


Fig. 151. — UttUago moydit. Maize -head 
completely malformed Into smut-boil*, which 
have not yet ruptured, (v. Tubeuf phot.) 


Fig. 152 . — Uttilago maydts. Smut-boil* on 
Htcm and leaf of a Maize-plant, (v. Tubeuf 
phot.) 


seedlings as well as growing points and ot her young parts of 
older plants. 

Infection may take place on any immature part of the 
host. The mycelium does not grow Jhrough the whole plant, 
but only inhabits a part in the vicinity of the place infected. 
The heads are most frequently attacked, with the result that 
the grain fails to reach maturity, or is destroyed during t In- 
formation of fungus-spores. 

Owing to the danger of infection, grain mixed with smut- 
spores should never be used for sowing ; nor can such be 
safely used for feeding cattle on account of its injurious effects 
on them. 


USTILAGO. 


281 


Knowles, 1 Cugini, 2 and Wakker 3 have investigated the 
anatomical changes produced by this fungus. The latter 
investigator found that the xylem -elements with unlignified 
walls remain incompletely developed, and have a peculiarly 
twisted course ; that normal sieve-tubes are absent ; that the 
cells of parenchyma undergo secondary division, and give rise 
to a new tissue provided with little fibrovascular bundles, and 
rich in starch-contents, in other words, a nutritive tissue to be 
used up in the spore-formation of the smut. 

The disease may be found wherever maize is cultivated, 
and often causes a very serious diminution in the harvest. 
It may be combated by early removal and destruction of the 
smut-galls. As a preventive measure, the treatment of seed-corn 
with copper sulphate solution 4 is recommended. The avoidance 
of fresh manure is also advisable, since conidia capable of germi- 
nation may be lodged in it. 

The following are the results of an experiment carried out 
at my instigation by Professor Wollny in his experimental 
plots at Munich. Three plots were selected distant from each 
other about 70 metres. On 2nd May, 1893, these were marked 
out in rows 40 centimetres apart, in which maize was sown at 
intervals of 50 c.m. The grain was previously mixed with 
smut-spores obtained from the Tyrol in autumn, 1892. Plot 
No. 1 was left without manure, No. 2 was treated with old. 
No. 3 with fresh cow- manure. Maize had never been grown 
in the vicinity, so that no infection could result from external 
sources. The results were : 

Smutted. 



Number of Plants. 

Absol. 

Per cent. 

Plot No. 1, unmanured, 

148 

0 

0 

„ 2, old cow-manure, - 

124 

2 

1-6 

„ 3, new cow-manure,- 

132 

11 

7-6 


Ustilago Schweinitzii Till, from Carolina U.S.A. is probably identical 
with list, maydis. 

Ust. Fischeri Pass. 5 This smut, observed in upper Italy, 

1 Knowles, E. J., Amer. Journal of Mycology, Vol. iv., 1889. 

2 Cugini, “ II carbone del grano turco,” Boll. dell. stat. Agrar. di Modena, 1891. 

3 Wakker, Pringsheim’s Jahrbuch, Bd. 24, 1892. 

4 See “General Part,” chap, vi., and also “ Vergleichende Untersuehungen 
iib. Flugbrandarten.” P. Herzberg in Zopf’s Beitrdgen, 1895. 

5 Passerini, Just’s botan. Jahrbuch, 1889, p. 123. 


282 


USTI LAG I N EA K. 


attacks the axis of the maize-heads. Its spores are spherical 
with slightly granular coats, and measure only 4-6 g. in diameter. 
It causes damage through shrivelling up of the grain. 

Ust. Reiliana Kuhn. This smut frequents Sorghum kcdepnisr 
and S. vulgare (Durra or Indian millet); also maize in various 
parts of Europe and America, 1 as well as in Egypt and India. 
It is called “ Hamari ” in the Arabic language. 

Kuhn 2 thus describes it : “ This species causes the ears of 
Durra to become large smut-galls of roundish or ovoid shape, 
with a height of 60-95 m.m. and a diameter of 40-60 ra.m. 
At first the smut is enclosed in a whitish skin, which is ruptured 
into shreds to allow the escape of the black spore-powder. 
After the smut-spores are shed, there remains a stiff skeleton 
consisting of the fibrovascular bundles of the aborted ear.” 

The spores are distinguished from those of Ust. maydis by 
their greater size (9-1 5/a), and their almost smooth membrane 
with very small spines. According to Brefeld, the spores are 
capable of germination in nutritive solutions after eight years. 
In the fresh condition they germinate in water to a limited 
extent, producing multicellular promycelia which give off conidia. 
In nutritive solutions they germinate and produce thick promy- 
celia with three or four cells, from which multitudes of conidia 
(5-12 g long and 3-5 g broad) are abjointed. The conidia 
fall off and sprout till the nutritive substratum is exhausted, 
when they give rise to thread-like conidia which do not coalesce. 
If kept dry the conidia easily retain their vitality for months. 

Kiilni distinguishes further Sorosporium Ehrenbergii Kuhn <>n Sorghum 

cernuum. 

Ust. cruenta Kuhn.'* Another parasite on the ears of 
Sorghum. It is described by Kiihn as follows: “On the 
spikelets little reddish-brown protuberances of roundish or 
oblong shape are formed and enclose moderately-sized masses 
of dark-red smut-powder. If the pustules are very numerous 
they coalesce with each other, and the branches of the ear 
become more or less shortened, thickened, and twisted. Where 

1 Norton, “Ustilago Reiliana,” Botauica! Gazette, 1895, p. 4t>2. 

-Kuhn, “Die Brandfonneu der Sorghuin-arten,” Mittheil d. Vtr.f. Erdk-uwh 
zit Halle, 1877. 

:l Kuhn {lor. rit.) and Hamburger Oarten-Zeitioig, Bd. ‘28. 

Brefeld, Heft v., p. 9t. 


USTILAGO. 


283 


the pustules are fewer in number the parts of the ear retain 
their normal position, but all the floral organs contained in 
the glumes are wholly or partially converted into irregular 
greyish smut- masses. Isolated pustules may occur under the 
inflorescence, on the next internode of the haulm.” 



Fig. 153. — U&tiLago cruenta. Smut of Durra or Sorghum. The head has been 
divided up and the isolated branches photographed. The ovaries are transformed 
to long crooked sacs, and pustule-like outgrowths are also present on stalklets and 
stalks, (v. Tubeuf phot, from material supplied by Prof. Dr. Jul. Kuhn.) 

The spores are yellow to brown in colour, smooth-walled, 
and of very variable shape, 5-12 /ul long and 5-9/x broad. As 
a rule, germination in water results in the formation of a germ- 
tube composed of four or five cells, which elongate to long 
mycelial threads or, exceptionally, produce a single conidium. 
As a result of germination in nutritive solutions, a lively 


284 


USTILAGINEAE. 


formation of conidia ensues ; the conidia multiply in a yeast- 
like manner, and only grow out as hyphae on exhaustion of 
nutritive material. Infection takes place on seedling-plants. 

Kuhn cultivated this species on Sorghum saccharatum and S. vulgare, 
and suggests that a common disease of Durra in South Africa may he 
caused by this parasite. 

Ust. sorghi (Link.) ( Ust . Tulasnei Kuhn) (U.S. America). 
This is another widely distributed parasite of Sorghum vulgare 
and S. saccharatum. Its external appearance is described by 
Kuhn somewhat as follows : “ Diseased plants attain to almost 
their normal size, and the flower-head is developed as far as 
the glumes. The ovary, however, is completely metamorphosed 
into a sac filled with spores, its outer wall forming a delicate 



Kio. 154 . — Uitilago cruenta. S pikelet 
enlarged from a head of Sorghum . The 
ovaries are transformed into long flask* 
shaped sacs, from slits of which the 
spores arc emerging as a black powder. 
J natural size. (v. Tubeuf del.) 



Fio. 165. — U*tilago cruenta. Germin- 
ating and sprouting conidia from a 
cultivation in plum-gclatinc. (v. Tubeuf 
del.) 


whitish coat, which is easily torn, and, when the spores have 
escaped; a columella will be found to occupy the centre of the 
smut-mass. The stamens may also become filled with spores, 
and be externally more or less irrecognizable. As a rule, all the 
flowers of a head are smutty; if any escape, they remain more 
or less rudimentary.” 

The spores, according to Brefeld, germinate only in nutritive 
solutions. They produce a four-celled promycelium, on which 
few conidia are formed. 

Ust. sacchari Rabh. Dust-brand of cane sugar. This fungus 
injures the stems and heads of Saccharum ojjicnialc, S. cyluutricum, 
and S. Erianthi in Italy, Africa, and Java. 

Ust. sacchari-ciliaris Bref. occurs on Saccharum cilia re near 
Calcutta. 

Ust. avenae (Pers.). The smut or brand of the oat occurs 


USTILAGO. 


285 


very frequently on Avencc sativa, also on Avenco orientalis, 
A. fatua, and A. strigosa in Europe and North America. So 
common is it that one seldom sees a field of oats free from the 
black smutted ears (Fig. 156). 

All parts of the flower are attacked, the ovary, stamens, 
glumes, and even the awns. The grains become filled with 
the black spore-powder, which shows through the transparent 



Fig. 156 . — Ustilago avenae. The Oat-smut on Avene. : sativa. (v. Tubeuf phot.) 

membrane of the ovary wall. The diseased ears emerge from 
their enclosing leaf-sheaths, and become exposed to wind and 
rain, under the effects of which the delicate membrane soon 
becomes ruptured and the spores are blown or washed away, 
till only the axes of the spikelet are left with a few ragged 
remains of the flower. As a rule every shoot of a plant and 
all the grains of an ear are attacked ; if single grains do escape, 
they remain poorly developed. 

The spores (5-8/x) have a smooth or slightly granular coat, and 


286 


USTILAGINEAE. 


retain tlieir capacity for germination for years. In water they 
germinate immediately, and produce a single (rarely two) promy- 
celium consisting of four or five cells, from the ends or partition- 
walls of which oblong conidia continue to be abjointed for about 
two days. The cells of promycelia may become connected with 
one another by lateral branchlets. Delicate germ-tubes are 
given off by the promycelial cells, by the conidia, or by secondary 
conidia. In nutritive solutions, on the other hand, the spores 
germinate much more vigorously, the promycelium is stronger, 
the conidia are continuously abjointed from little sterigmata, 
and go on sprouting in a yeast-like manner till, on exhaustion of 
the nutriment, they germinate to form vigorous mycelial filaments. 
The fusion of the cells of promycelia never takes place in nutritive 
solutions. 

The infection of oat-plants takes place on the soil by means of 
the germ-tubes produced from the conidia, promycelia, or spores. 1 
These infect the first leaf-sheath — that one which on germination 
emerges from the ruptured seed-coats as a whitish or yellowish- 
green shining shoot, and continues to grow as a sharp-pointed 
cylinder till, pierced by the first green leaf, it dries up. In 
36 to 48 hours after infection, mycelial threads were found 
to have pierced the epidermal walls, and to have branched freely 
in the tissues. The mycelium grows from the leaf-sheath into 
the first green leaf, passes straight through it into the second, 
and so on till it reaches the haulm or stem. 2 The young 
mycelium grows steadily onwards, and the plasma of older 
hyphae passes over into it. In this way the fungus keeps 
pace with the host-plant, exhibiting externally no symptom 
of its presence till the flowers are reached, where the chlamydo- 
spores are formed. 

Sterilization of seed-corn by Jensen’s hot-water method is 
strongly recommended. 3 In America, steeps containing potassium 
sulphide, copper sulphate, or lime are also used. As preventive 
against infection, late sowing is advisable. This is founded on 
Brefeld’s investigations, in which he found that oat-smut germin- 

1 Wolf, Der Brand den Uetreide ■», 1S74. 

s According to Ktthn, and in Brefeld’s infections (Heft xi., 1895), the majority 
of the germinating conidia are said to penetrate into the young shoot-axis. 

1 “ Treatment of Smuts of Oats and Wheat,” U.S. De/xirtment of Agncultun . 
Farmers' Bulletin Xo. 5, 1S92 ; “Grain-smuts and their prevention," Yearbook 
of U.S. Dept, of Agriculture, 1894. 


I'STILAGO. 


287 


atecl best at 10 C., and not so well above 15°C. This 
conclusion is supported by experiments of Ivellermann and 
Swingle. Neither these investigators nor Jensen, however, agree 



Fig. IbT.—Uslilago perennans on Arrhenatherum elaliv.s (Oat grass). The grains 
are transformed into black smut-masses ; the appearance of the infected spikelets 
is quite distinct from that of the healthy one to the right, (v. Tubeuf phot.) 


with Brefeld’s view, that the fungus is introduced into fields- 
with fresh farmyard manure. 

Kellermann and Swingle have found a smut on oats in America which 
they distinguish as Ust. avenae var. lexis. 

Ust. Kolleri Wille. This is another species of oat-smut recently dis- 
tinguished ; it has smooth spores, and is said to cause even greater damage 
than Ust. avenae. 


288 


L'STILAGINEAE. 


Ust. perennans Rostr. 1 * This smut or dust-brand occurs 
frequently in the flowers of Arrhenatherum elatius (Fig. 157). 
The mycelium perennates in the rhizome. 

An Ustilago nearly allied 
to the preceding one occurs 
also on Festuca pratensis, 
Lolium perenne, and other 
grasses. 

The Smut of Barley. 
There are really two species 
of Ustilago found on barley, 
Ust. hordei and Ust. nuda. 
Ust. hordei (Pers.) (Ust. 
Jenseni Rostr.) (Britain and U.S. America). This has black 
spherical spores (6 - 5 to 7'5/jl in diameter), which germinate 
and give off conidia from a promycelium. The spikelets gene- 
rally remain enclosed in their coverings. Treatment of seed- 
corn with a half per cent, copper steep is a certain remedy. 

Ust. nuda (Jens.) (U.S. America). In ears diseased by this 
smut the epidermis of the glumes is early lost, so that the 
spore-powder lies freely exposed when the ears emerge from 
the leaf-sheath. The spores on germination give off a four- 
celled promycelium, which however produces no conidia, but 
develops directly to a septate mycelium. The spores are 
smooth-coated and oval (5-7/a long and 5-6’5/u broad); they 
are matured and set free at the flowering season of the barley, 
and probably infect seedlings in spring. The spores of this 
smut are very resistant against treatment with copper steeps, 
and it is recommended to soften the barley for several hours 
in cold water before applying Jenson’s method. 

Ust. tritici (Pers.) (Britain and U.S. America). Wheat-brand. 
'The spores are developed in the ovary of the wheat, and are 
black with a tinge of olive-green. On germination they im- 
mediately form a uon-septate mycelium (Fig. 1G0). 

Henning 4 lias described spore-cushions on the leaves and leaf-sheaths of 
Triticum vutgare in Upper Egypt. 

Ust. bullata Berk, on Triticum orientate in Turkestan. 



Flo. 158 . — UUilago perennan*. Sporc-culturc 
in plum -gelatine, (v. Tubeuf del ) 


1 Rostrup, (latitaffineac Danin t, 1890. 

-Henning, Zcitschrijl /. Tfl anzenkrauLheitai, 1894. 


USTILAGO. 


289 


Ust. secalis Rabenh. Rye-brand. This occurs but rarely, 
and destroys only the grain. 

Ust. panici-miliacei (Pers.) ( Ust. destruens Duby). Smut 
ot Millet. This smut occurs on the flowers of Panicum milia- 



Fig. 15!).— Ustilago hordei. Barley-smut on Hordev.m distichum. (v. Tubeuf phot.) 

cemn, P. chartaginiense, and P. Crus-cjalli in Italy, France, 
Germany, and North America. Sometimes it is very abundant 
and causes great damage. The mycelium makes its way into 
young plants and grows upwards with them, penetrating every 

T 



290 


USTILAGINEAE. 


shoot. Spores are developed only in the inflorescence, which 
in consequence fails to reach its full development as a panicle, 
and remains more or less spike-like and enclosed in a leaf- 
sheath. The parts of the inflorescence become completely filled 



Flo. KiO.— Utlilago tritici. Wheat-smut. The central ear 1b normal and 
healthy, the others are smutted and most of the spores are already shed. 

(v. Tubcuf phot.) 

with a sporogenous mycelium from which arise the spore-masses; 
these are at first enclosed in whitish coverings consisting of 
tissues of the host-plant, but when mature they escape as a black 
dust or powder. 


USTILAGO. 


291 


The spores are smooth-coated and spherical or elliptical, 9-1 2 /x 
long, and 8- 1 0 /x broad. According to Brefeld, they germinate 
in two or three days in water, and produce promycelia with four 
or five cells ; the cells may either bud out directly and become 
hyphae, or do so after previous fusion. 

Spores placed in nutritive solutions germinate in about three 
days, and produce several strong septate promycelia with spindle- 
shaped conidia. The conidia as a rule germinate directly into 
branching hyphae ; fusion of conidia is not known, and secondary 
conidia are only rarely formed. The hyphae become septate 
in their older parts, and produce conidia in two ways, firstly, 
from hyphae in the solution itself ; secondly, from aerial hyphal 
branches which rise out of the solution and give off conidia 
in a manner similar to mould-fungi. 

Brefeld states that infection takes place by means of the 
germinating conidia. Only resting-spores are produced on the 
plant itself, and these retain their capacity for germination 
for years. 

Ust. Rabenhorstiana Kuhn 1 (U.S. America). This is found 
on Panicum miliaceum, P. glabrum, P. lineare, and P. sanguincde. 
It destroys flowers, ears, and upper part of haulms. The spores 
are brown and spiny ; they germinate, but do not produce 

conidia. 

Ust. sphaerogena Burrill. An American species causing 
distortion of the spikelets of Panicum Crus-galli. The malforma- 
tions resemble those produced on the same host by Tolyposporium 
bullcitum, but differ in having a rough surface with short rigid 
hairs. The spores are free and germinate easily in water, 
producing promycelia which give off conidia. The conidia 
frequently sprout for a time in a yeast-like manner. 

The following are American species : 

Ust. diplospora Ell et Ev. On Panicum sanguincde. 

Ust. trichophora Lk. On Panicum colinum. 

Ust. setariae Rabli. On Panicum sanguiaale ; probably identical with 
Ust. Rabenhorstiana. 

Ust. panici-leucophaei Bref. On Panicum leucophaeum in Rio de Janeiro. 

Ust. digitariae Kze occurs on the flowers of Panicum 
(Digitaria) sanguincde , P. glabrum , and P. repens. The spores 

are smooth-walled. 


1 Kuhn, Hedwigia , 1S76. 


USTILAGINEAE. 


292 

Ust. panici-frumentacei Jiref. 1 is found on Panicum frumen- 
laceum, a cultivated Himalayan millet. Only isolated grains 
in an ear are attacked, becoming enlarged to twice their 
normal size. Germination of spores takes place sparingly in 
water, but abundantly in nutritive solutions. Two-celled promy- 
celia are produced bearing numerous sprouting conidia. On 
exhaustion of nutrition, the conidia give off one or two filaments 
on the surface of the liquid, and from these other sprouting 
conidia arise. 

Ust. Crameri Korn, completely destroys the ovaries of Setaria 
italica, S. viridis, and S. ambigua, leaving only the outer wall 
as an enclosure for the spore-powder. The spores are brown, 
smooth-walled, and 6-9 n broad, 10-12/x long. The promycelia 
consist of four or five cells, which in water as well as nutritive 
solutions grow out into long threads without producing conidia. 

Ust. neglecta Xiessl tills with its black spore-powder the 
ovaries of Setaria glauca, S. verticillata, and S. viridis. The 
cells of the promycelium develop into a mycelium without pro- 
duction of conidia. 

Ust. Kolaczekii Kiiliti. On Setaria geniculata in Berlin Botanic Garden. 

Ust. bromivora Fisch. (Britain and U.S. America). This 
appears in flowers of species of Pronins, so that the ovaries 
become filled with a dark-brown or black spore-powder, but 
the glumes or heads undergo no deformation. The spores are 
smooth, and on germination in water produce only a spindle- 
shaped one-celled (rarely two-celled) promycelium ; in nutritive 
solutions, Brefeld found they generally produced two-celled 
promycelia, bearing conidia from which are produced further 
promycelia with conidia : yeast-like colonies are never formed. 

Ust. ischaemi Fuck, attacks Androjwgon Ischaanuin. The 
inflorescences remain almost completely enclosed in the upper- 
most leaf-sheath, and are destroyed except their axes. The 
spores are brown and smooth-walled. Brefeld states that in 
nutritive solutions they produce conidia which remain adherent 
to the promycelium and grow out into long hyphae without 
coalescing. 

Ust. andropogonis-tuberculati Bref. on Andropogon tultercn latum from 
Simla. 

Ust. andropogonis-annulati Bref. on Andropogon annulatnm from Calcutta. 

'Brefeld, Schi linnet pilze, Heft XU., 18 !C>. 


USTILAGO. 


293 


Ust. grandis Fries. Eeed-smut. (Britain.) This frequents the 
haulms of Phragmites communis (also Typha latifolia and T. 
minor ) ; the internodes of the host in consequence swell out 
and appear as if the stem carried one or more bulrush-heads. 
The mycelium permeates the whole host-tissue and produces 
spores, which escape as a black dust on rupture of the epidermis. 
According to Kuhn, the spores are capable of immediate ger- 
mination and retain their vitality for a whole year. A 
four-celled promycelium is produced and becomes detached from 
the spore ; then follows an abj unction of oblong conidia from 
the septa of the promycelium. In nutritive solutions, Brefeld 
found that germination took place in the same way, hut more 
rapidly and vigorously. Numerous conidia are produced, but 
these only rarely give off secondary conidia, and then only a 
single one ; more commonly they produce promycelia, as the 
spores did, and conidia again arise from these ; yeast-like 
sprouting does not occur. The resting-spores may continue 
to give off promycelia in succession for some time. On ex- 
haustion of nutrition the cells of the promycelium, as well 
as the conidia, develop into mycelial threads, to which alone 
Brefeld ascribes the capacity for infection. 

Ust. longissima (Sow.) (Britain and U.S. America). This 
forms elongated brown spore-patches on the leaves of various 
species of Glyceria. Brefeld states that the smooth spherical 
spores germinate in water, and give off a short unicellular 
promycelium which undergoes no further development. In 
nutritive solutions the spores germinate in like manner, but 
the promycelium becomes thread-like and septate, and gives 
off conidia laterally ; new promycelia continue to be given 
off from a cell which remains behind inside the spore, and the 
conidia ultimately develop into hyphae. 

Ust. hypodytes (Schlecht). This species forms dark smutty 
coatings on haulms and leaf-sheaths of Glyceria Jluitans, Dip- 
lachnis fuscci, Agropyrum repens, Calamagrostis epigea, Psamma 
arenaria, Stipa pennata and S, capillaris, Bromus erectus, Triticum 
npcns and T. vulgare , Elymus arenarius, Panicum repens, Phrag- 
mites communis, Arundinaria, etc. The spores are brown, 
smooth-walled, and irregularly spherical or quadrangular ; they 
germinate in water or nutritive solutions, producing mycelia 
direct, without previous formation of conidia. 


294 


U.STILAGINEAE. 


Ust. gntmmica B. et B. is reported on haulms of Aira and Glycerin 
in England. 

Ust. echinata Sehroet. produces smut-strips on leaves of Phaluris 
arundinacea. (U.S. Amer.) 

Ust. cynodontis Henn. On Cynodon Dactylon from Sinda. 

Ust. arundinellae Bref. On Arundinella near Calcutta. 

Ust. aristidae-cyanthae Bref. On Aristide, cyantha from Himalaya. 

Ust. coicis Bref. On Coix lacryma from Simla. 

Ust. esculenta Henn. 1 causes deformation of plants of Zizania latifolia 
in Tonquiu and Japan. The deformed parts are eaten, while the spores 
are used for dying of hair and eye-brows, as well as in the manufacture 
of a varnish. 

Ust. paspalus-dilatati Henn. On Paspalvjs dilatatus. 

Ust. olivacea IJ. C. frequents species of Care. The olive- 
brown spore- masses hang loose and fleecy from the destroyed 
ovary. The spores, according to Brefeld, are produced from 
long hyphae which become thickened at intervals and broken 
up by cross-septa into portions corresponding to the future 
spores. The hyphae, however, are not completely given up to 
spore-formation, but parts remain and form fine filaments which 
give the fleecy appearance to the ruptured ovaries. Germina- 
tion in water results in the formation of a single conidium, a 
second being rarely formed. In nutritive solutions similar 
conidia are produced one after another successively, and sprout 
off conidia in a yeast-like manner without the formation of pro- 
mycelia. On failure of nutriment, hyphae are finally produced. 

Ust. Vuijkii Oudem. et Beyerk. The ovaries of Luzula 
campesfris become filled with spores, some colourless, some 
light-brown. The spores germinate in water, giving four-celled 
promycelia with ovoid conidia, which do not, however, coalesce 
or develop further, even in nutritive solutions. 

Ust. capensis Rees. In fruit of Juucus. 

Ust. luzulae Sacc. In fruit of Luzula. 

Ust. scabiosae (Sow.) 2 (Ust. flosculorum Tub). (Britain.) The 
anthers of Knautia and Srabiosa attacked by this fungus become 
filled with a flesh-coloured to violet spore-powder, and swell 
to little sacs. The flowers otherwise are but little altered. 
Brefeld found that spores from Knautia arvensis germinate 
easily and abundantly in water, and produce promycelia con- 

1 1’. Hennings, Ifalwigia, 1895: Miyuhe, Tokio tlotanical Magazine, 1895. 

2 Fischer v. Waldheim, Hot. Zt itung. 18(i7. 


USTILAGO. 


295 


sisting of three or four cells with conidia, and sometimes 
secondary conidia. Coalescence of conidia may take place, and 
thereafter production of little mycelial threads. In nutritive 
solutions everything proceeds more luxuriantly, and conidia are 
produced in large numbers ; they are easily detached and sprout 



Fio. 161 .— Ustilago tragopogonis. Plants of Tragopogon in flower and fruit— 
1, normal fruit ; 2 and 3, normal flowers ; 4, two normal flower-buds. The 
remaining specimens are attacked by the fungus, and, in consequence, remain 
in the bud condition, and filled with black spores which escape by the opening of 
the involucre, (v. Tubeuf phot.) 


yeast-like, till, on deficiency of nutrition, fusion and subsequent 
germination takes place. 

Ust. intermedia Schroet. ( Ust. Jlosculorum I). C.) (Britain). 
The anthers of Scabiosa Columbaria become filled with the dark 
violet spores of this smut. The spores germinate in water, 
and, according to Brefeld, produce three-celled promycelia with 
few conidia ; some of these, as well as the cells of the promy- 



206 


USTILAGINEAE. 



celia, may develop to mycelia; coalescence of conidia is unknown. 
In nutritive solutions conidia are formed in large numbers, and 
multiply yeast-like till nutriment fails. 

Ust. succisae Magn. 1 frequents the anthers of Scabiosa Succisa, 
and forms pure white spores, easily distinguished from those 
of the two preceding species. The anthers appear to be thickly 
covered with glassy granules. The spores produce four-celled 
promycelia from which conidia are formed. (Britain.) 

Ust. tragopogonis (l’ers.) (Britain). 
This fungus forms its spores in flowers 
of species of Tragopogon, and in many 
localities has a wide distribution. 
The development of the flower is 
retarded, so that it retains externally 
the appearance of a Hower-bud en- 
closed in its bracts (Fig. 161). The 
dark-brown or violet spores escape 
through intervals between the bracts; 
they are 13-17/u long, 10-ln/u broad, 
with reticulate markings on their 
coats. They easily produce in water 
four or five-celled promycelia from 
which conidia are given off, often 
followed by coalescence. In nutritive 
solutions development is much more 
vigorous, secondary conidia may he 
produced, and coalescence always takes place. 

Ust. scorzonerae (Alb. et Schwein.) is at first sight very 
similar to Ust. tragopogonis. Its spores are found in flowers 
of Scorzonera humilis, Sc. purpurea, and cultivated species, e.g. 
Sc. hispanica ; while its mycelium hibernates in the perennial 
root-stocks of these. The spores are produced rapidly and 
in large numbers ; they germinate easily in water, forming a 
four-celled promycelium, and thereafter conidia which do not 
pair. 

Ust. cardui Fisch. v. Waldh. (Britain). This is the cause 
of a stunting of the flower-heads of Carduus acanthoides, C. 
nutans , and Silybum Marianum, while at the same time they 
become filled with a brownish-violet spore-powder. The spores 
1 Magnus, Hediriyia, 1875. 


Fio. 162. — Uitilago tragopogonii. 
Development of spores: successive 
stages of development, in order of 
the letters, a, Sporogenous branch, 
just appearing on the surface of 
young corolla of Tragopogon pro- 
lentil, and beginning to form a tuft 
of branchlets. b and c, Formation of 
spores from the mycelium. <1, Spore, 
clump with several ripe spores, the 
episporium of which is coloured 
dark-violet and thickened in a 
reticulate manner, (x 300). (After 
I)e Bar}’.) 


USTILAGO. 


297 


are about 20/* in diameter, and form in water promycelia with 
eonidia. In nutritive solutions Brefeld found conidia produced 
in large numbers, and multiplying by yeast-budding. The 
promycelial cells grow out as septate branched twigs, from 
which conidia are abjointed, and after coalescing in pairs, produce 
germ-tubes. 

Ust. violacea (Pers.). 1 Carnation-smut (Britain and U.S. 
America). In Silene, Viscciria, Saponaria, Dianthus, Stellaria, 
Malcichium, Cerastium, and Lychnis, the pollen sacs of other- 
wise well-developed flowers become filled with dark-violet 
spores, which escape and discolour the other floral parts. 
Pistillate flowers of Lychnis attacked by this fungus develop 
stamens containing the smut-spores (p. 27). On germination 
in water, promycelia of three or four cells are formed, and 
become detached from the spores. Primary and even secondary 
conidia are produced, while coalescence of promycelial cells and 
conidia is common ; but only a few of them produce germ- 
tubes. In nutritive solution, according to Brefeld, everything 
proceeds much more vigorously; from tiny conidiophores on the 
promycelia numerous conidia are produced in succession, and 
from these other conidia are budded oft' like yeast-cells till 
nutriment fails, when they grow out to form hyphae. The 
conidia are longer than those formed in the water-cultures, 
and coalesce in pairs to give rise to longer and stronger 
germ-tubes. 

Ust. holostei De Bary on Holosteum urnbellatum. The host-ovaries 
become filled with spores which germinate to four-celled promycelia from 
which pairing sporidia are formed. 

Ust. Duriaeana Tul. In the ovary of Cerastium. 

Ust. major Schroet. On Silene Otites. The spores germinate only in 
nutritive solutions. (Britain.) 

Ust. seminum Juel. In the ovules of Arabis petraea in Scandinavia. 
The spores on germination produce simple hyphae. 

Ust. entorrhiza Schroet. In root-cells of Pisum sativum. 

Ust. pinguicolae Iiostr. On Pinguiculct vulgaris in Denmark. 
According to Brefeld, the spores germinate equally in water or 
nutritive solutions, forming three-celled promycelia, which separate 
from the spore and bud off conidia from each cell. 

1 Tulasne, Ann. cl. sciences natur., Ser. hi., Vol. vii., 1847. 

Atkinson (American Carnation Society, 1893), describes this and other smuts 
frequenting American Carnations. (Edit.) 


298 


USTILAGINEAK. 


Ust. betonicae Beck . 1 occurs in the anthers of Bdonica 
Alopecurus. Its spores are larger than those of Ust. violacea, 
and have larger-meshed reticulations on the spore-coat. The 
spores germinate in water, and as a rule produce a three-celled 
promycelium from which conidia are abjointed. These at once, 
or after production of conidia, coalesce in pairs and give off germ- 
tubes. In nutritive solutions germination takes place much 
more vigorously, numerous conidia are formed and continue to 
bud off new conidia till the nutriment is exhausted, when 
coalescence of conidia and development of liyphae takes place. 

Ust. bistortarum D. C. frequents leaves of Polygonum and 
Rumex. (Britain and U.S. America.) Brefeld states that the 
spores are dark-red and germinate to four-celled promycelia, 
from which conidia are produced and readily coalesce, especially 
in presence of abundant nutriment. 

Ust. marginalis ( Lk.) on Polygonum Bistorta. The spore-masses 
are dark-violet, and occur chiefly on the margins of the leaves. 
The spores germinate in water and produce a four-celled promy- 
celium with oval conidia, which do not sprout, but either pair 
or grow out as hyphae. 

Ust. anomala Kunze. On leaves and in ovaries of Polygonum (U.S. America . 

Ust. utriculosa (Nees). In ovaries and anthers of Polygonum. The 
greyish-violet spores, Brefeld says, germinate during the following summer, 
and give off four-celled promycelia with conidia which do not coalesce in 
pairs. (Britain and U.S. America.) 

Ust. Parlatorei Fisch. On twigs and leaves of Rumex maritimus and R. 

obtusifolius. 

Ust. Kuhneana Wolf. Inhabits all parts of Rumex Acetosa and R. Aeeto- 
sella (Britain). 

Ust. Goeppertiana Schroet. On Rumex Acetosa , especially in leaves and 
leaf-petioles. The spores germinate in water or nutritive solution. The 
promycelium is unicellular and remains inside the spore, giving off a single 
conidium, which for a time buds off other conidia ( Ust. olivacea alone behaves 
in this same way). 

Ust. Molleri Bref. On Polygonum hispidum. 

Ust. Koordersiana Bref. On Polygonum burbot nm in Java. 

Ust. domestica Bref. On Rumex domesticus in Norway. 

Ust. vinosa (Berk.). On fruits of Oxyria (Britain and U.S. America). The 
spores germinate in water or nutritive solutions, and produce a four-celled 
promycelium from which conidia are given off, especially in nutritive 
solutions ; the conidia ultimately produce germ-tubes. 


Zoolog. -botan. Quell., Vienna, ISSO. 


USTILAGO. 


299 


Ust. Vaillantii Tul. 1 appears in the anthers and ovaries of 
Gagea, Scilla, Mtiscari, etc. The perianth of diseased dowers 
remains, but is somewhat enlarged. The ovaries and anthers 
become filled with spores ; the latter organs are, however, fully 
developed and may even contain pollen-grains mixed with spores. 
According to Brefeld, the spores germinate easily in water and in 
nutritive solution. A promycelium is formed which, after detach- 
ment from the spore, becomes three-celled and develops conidia. 
These sprout for some time, then produce three-celled promycelia. 

Ust. ornithogali (Schm. et Kze) forms leaf-swellings on Ornithogalum and 

Gagea. 

Ust. tulipae (Henri.) produces swellings on the leaves of the tulip. 

Ust. plumbea Rostr. occurs on leaves of *1 rum maculatum in Denmark. 

Ust. ficuum Reich. In the fruits of Ficus Carica in Asia Minor. 

Ust. Trabutiana Sacc. In berries of Dracaena Draco in Algeria. 

Ust. Vrieseana Vuill. 2 In the Botanic Garden at Amster- 
dam, the roots of several species of _ Eucalyptus exhibited woody 
tumours from which proceeded outgrowths resembling “ witches’ 
brooms.” These contained the mycelium of an Ustilago which 
produced spores in the cortical tissues. 

Ust (?) adoxae Bref. On Adoxa nioschc/tellina in cells of the subterranean 
stem. The spores produced only simple filaments without conidia. 

Ust. Lagerheimii Bref. On Rumea from Quito. 

Ust. Schweinfurthiana Thlim. On Imperata cylindrica from Cairo. 

Ust. boutelouae-humilis Bref. On Bouteloua humilis from Quito. 

Ust. Ulei Henn. On Chloris. 

Ust. spinificis Ludw. On Spinifex hirsuta from Adelaide, Australia. 

Ust. Treubii Solms. 3 This Javanese fungus and the galls 
produced by it deserve a somewhat lengthened notice on account 
of their general biological interest. It causes a hypertrophy on 
Polygonum chinensc in Java, which further exemplifies the 
phenomena already noticed in connection with Caeoma deformans 
on Thujopsis (p. 30). 

The stems at attacked places show strong hypertrophy and 
great change in their anatomical structure. Solms designates 
the thickenings, in common with those caused by Caeoma 

'Tulasne, Ann. d. science natur., Ser. hi., Vol. vii., 1847, with plates of Muscari. 

Worth G. Smith (Gardener’s Chronicle, xv., 1894, p. 463), gives a figure 
and note on occurrence of this smut in Britain. (Edit.) 

2 Vuillemin, Compt. rend., 1894. 

3 Solms, Anna/, du jardin boian. de Buitenzorg, Vol. vi. , 1886-87, p. 79. 


300 


USTILAOINEAE. 


deformans and Peridermium elatinum, as “ vegetative canker- 
galls.” On those places are crowded fleshy brittle outgrowths, 
consisting of an irregular bent club-like stalk, longitudinally 
furrowed, and expanded at its upper extremity into a broadened 
head containing the Ustilago spores. Solrns calls these out- 
growths “ fruiting galls ,” 1 and he describes them as follows : 
“ if one of these protuberances be divided, the spore deposit will 
be found as a flattened violet layer, extending to the margins 
of the head and roofed in by a slight plate of tissue. This 
last becomes ruptured, shrivelled, and brown. The violet 
spores are thus set free, along with a loose woolly capillitium- 
tissue, which apparently facilitates distribution of the spores 
by rendering them difficult to moisten, a contingency very 
likely to happen in the heavy tropical iains of Java, and with 
the result that germination would occur before the spores had 
time to be transported to a new host. After shedding of the 
spores, the succulent stalk remains. The fruit-galls consist of 
a hypertrophied tissue developed from the cambium; they first 
emerge as roundish naked protuberances, covered externally by 
a smooth epidermis, and containing a meristem from which 
fibrovascular bundles are developed. The galls are composed 
of a homogenous parenchyma of large thin-walled cells, elongated 
in the direction of the long axis of the galls, and containing 
large cell-nuclei. The epidermis consists of little, polygonal, 
nucleated cells, and is pierced by a few stomata. The galls 
are internally permeated by a number of irregularly arranged 
fibrovascular bundles which show a slightly developed wood 
and bast region. As the anterior end of the fruit-gall elongates, 
the bundles keep pace by repeated forkings, and form a 
system of branches diverging at very acute angles and ter- 
minating a short distance from the surface of the gall. The 
violet-brown sporogenous layer is situated just at the termination 
of the bundles, and is covered by a slight layer of parenchyma 
under the epidermis. The sporogenous layer appears as if 
composed of columns arranged beside one another in a palisade 
manner, and connected above and below with the enclosing 
tissues. At the margins of a section the columns easily separate, 
and will be seen to consist of a central strand of elongated 
cylindrical cells filled with a reddish gum-like mass. The cells 

' FruehtgiiUen. 


USTILAGO. 


301 


belong to the tissue of the Polygonum and may form simple 
filaments, or several such filaments may become bound together 
by lateral connections. Each strand becomes surrounded by 
spores of the Ustilago which are set free on rupture of the 
fruit-gall, while the cell-strands laterally bound to each other 
are loosened from the surrounding tissue as the capillitium. 

“ The spores germinate in water, producing short unicellular 
promycelia and fairly large conidia, which coalesce before they 
germinate. The mycelium is confined to a small part of the 
stem, twigs, or inflorescences of the host-plant. The hyper- 
trophied parts of the stem contain abnormal spongy wood, 
which easily decomposes and brings about the death of the 
galls, along with parts of the stem situated beyond them, or 
even the whole plant. The normal production of cambium is 
completely destroyed in the galls. The pith and primary rind, 
however, remain uninfluenced. The cambium produces, both 
outwards and inwards, such a mass of thin-walled parenchyma 
that the normal bast is forced asunder and disarranged. In 
this way rupture of the sclerenchyma-layer ensues, whereby the 
primary rind is destroyed, and the abnormal tissue formed by 
the cambium emerges to view. It is from such places that 
the excrescences described have their origin.” 

It will be seen we have here the partners of a symbiosis 
becoming so adapted to each other that the host-plant produces 
a special tissue for the distribution of the spores. This case 
goes further than most of those already mentioned in § 5 ; 
but the bushes produced by Cacoma deformans for the formation 
of its spores are again a distinct advance on the “ fruit-galls ” 
of this Ustilago. 


Cintractia. 

Spore-masses developed inside a stroma and passing outwards 
so that the mature black spores lie freely exposed. 

Magnus 1 lias recently separated Ustilago caricis Pers. and U. subinclusa 
Korn., and placed them under this genus, because their spores are developed 
only in the epidermal cells of the host-ovary. 

Cintractia caricis (Pers.) 1 (Britain and U.S. America). The 

1 Cornu. Aimed, d. sciences natur., Ser. vi., Vol. xv., 1883. Plate XV. 
Magnus, Botan. Verein d. Prov. Brandenburg, x.xxvn. Brefeld, Schimmclpilz , 

Heft xii., 1895. 


302 


USTILAGINEAE. 


mycelium forms a 
spores originate and 


Fk:. 103. — Cintrnctia caricit. 
Two ovaries have been replaced 
by black spherical fungus-fruits ; 
an isolated normal triangular 
ovary is shown in longitudinal 
and cross section, (v. Tubeuf 
del.) 

abjointed, while from 
produced. Numerous 


stroma on the ovary-wall ; there the 
pass out to the periphery as they attain 
maturity. The spores adhere in black 
masses, and germinate in water in the 
following spring. A promycelium is pro- 
duced, and on emerging into the air 
becomes divided by means of a cross- 
septum towards its apex ; from both 
cells so formed conidia are developed 
and grow out into germ-tubes without 
previous sprouting. This species occurs 
on many species of Carex, and the 
mycelium perennates in the rhizomes. 
The spores vary somewhat on the 
different hosts. 

C. subinclusa (Korn.) (U.S. America). 
The spores form coal-black masses in the 
ovaries of many species of Carex. They 
develop on a stroma from within out- 
wards, and are more easily detached than 
those of C. caricis ; their coat-markings 
also take the form of thicker and shorter 
processes. On germination in water 
after a resting period, the spores produce 
two-celled promycelia, from the apical 
cell of which an ovoid conidium is 
the lower cell a lateral conidiophore is 
conidia are given off from both cells, and 


grow out without previous sprouting. 


C. (1) torghi (Endothlaspii torghi) Sor. The mycelium envelopes the grain of 
Sorghum cernuum, and fills it with black spore-masses. It has only been 
observed in Asia* 

Other species of Cintractia occur outside of Europe, but are of no 
practical importance. 


Sphacelotheca. 

The sporocarp is sharply defined, and consists of a columella 
round which the loose mass of spores is disposed, the whole being 
enclosed in a covering formed by non-sporogenous hyphae. 

Sphacelotheca hydropiperis (Sclmm.). De Bary describes 


SPHACELOTHECA. 


303 


this funo-us as follows: 1 “ Sphcccelotheccc forms its compound 
sporophore in the ovule of its host. When the ovule is normally 
and fully developed in the young flower, the parasite, which 
always grows through the flower-stalk into the place of insertion 
of the ovary, sends its hyphae from the funiculus into the ovule, 
where they” rise higher and higher and surround and penetrate 
its tissue to such an extent as ^ 

almost entirely supplant it, and 
thus an ovoid fungus-body of 
densely interwoven hyphae takes 
the place of the ovule. The 
micropylar end ot' the integu- 
ments alone escapes the change, 
and remains as a conical tip 
(Fig. 164 C ) on the apex of the 
fungus-body and gradually turns 
brown and dries up. The fungus- 
body is at first colourless and 
uniformly composed of much- 
branched hyphae, which are 
woven together into a compact 


A - )\ 


\ I 

\Sv 

A 

; . 


u 


mass 


and have the gelatinous 



walls of the simple sporophore of 
Ustilacjo to be described below. 

If it has retained its ovoid 
form as it steadily increased 
in volume, differentiation begins 
first in the apical region into a 
comparatively thick outer wall 
which is closed all round, an 
axile columnar cylindrical or 
club-shaped body, the columella, 
both parts remaining colourless, 
fills the space between the two and becomes of a dark violet 
colour (Fig. 164 C, D). The lower part which corresponds to 
the funiculus and chalaza of the ovule remains undifferentiated, 
and an abundant formation of new hyphae is constantly taking 
place in it. This new formation is so added from below to 
the differentiated portion, that the latter constantly increases 
1 De Bary, Morphology and Biology of the Fungi, English Edition, p. 173. 


Fig. 1(54. — Sphacelotheca hydropiperis in the 
flower of Polygonum Hydropiper. A, Ripe 
compound sporophore of the fungus project- 
ing from the perianth of the Polygonvjv . 
B, The same, with the mass of spores emerg- 
ing from the sporophore. C, Median longi- 
tudinal section through a young fructifica- 
tion and its environment. D, Longitudinal 
section through an older sporophore. c, The 
columella, p, The perianth, f, The wall of 
the ovary, o, The integument (micropyle) of 
the ovule, g, The style. In C and D the 
sterile or young tissue of the fungus is 
shaded by longitudinal lines, the mass of 
ripening spores is darker. Further explana- 
tion in the text. (Slightly magnified.) 
(After De Bary.) 

and a dense spore-mass which 


304 


USTILAGINEAE. 


in height without becoming materially broader, and maintains 
therefore the form of a cylinder pointed at the upper end. 
Where the parts below approach the wall, columella, and spore- 
mass, they assume their structure and colour. In other words, 
each of the three portions grows from its base by addition of 
new tissue-elements, which are constantly being produced and 
pushed onwards from a basal formative tissue, and are differen- 
tiated and assume their ultimate form in the order in which 
they are produced (Fig. 164, C and D). The development 
and mature structure of the spore-mass are the same as those 
of Ustilago, which will be described presently. The wall in 
its fully developed state is a thick coat formed of many irregular 
layers of small round cells not very firmly united together. 
These cells are formed in the same way as the spores from 
the hyphae of the primary tissue, and are of about the same 
size as the spores with a delicate colourless membrane, and 
for the most part with watery hyaline contents. The columella 
has the structure of the wall, but it usually incloses in its tissue 
evident brownish fragments of the tissue of the ovule, and 
consists at its uppermost extremity of much larger, firmer 
hyaline cells, the origin of which I am unable to explain. 1 
may also observe that the upper extremity in young specimens 
always ends blindly in the spore-mass (C), but in some older 
ones reaches to the apical portion of the wall and passes into 
it {D)\ it is still uncertain whether this is a difference in the 
individual plants or a difference of age. 

“ The spore-receptacle which has now been described is formed 
only from the ovule. The perianth and stamens of the flower 
continue in their normal state. The wall of the ovary and the 
style are also not attacked by t lie fungus; they do not follow the 
growth of the spore-receptacle, and as this advances the lateral 
wall is distended and at length bursts transversely ; the style 
with the upper portion of the wall dries up into a small point 
at the apex of the receptacle, which is borne by the latter as 
it grows out of the perianth (.4). The wall of the spore- 
receptacle, especially where it is covered above by the withered 
remains of the wall of the ovary, is very fragile, and tears 
asunder at the slightest touch to discharge the spores (/>).’’ 

The dark-violet spores have a finely-warted exospore. 
According to Ihefeld, they germinate in water after a resting 


SPHACELOTHKCA. 


305 


period, and produce three-celled promycelia with elongated ovoid 
conidia, which sprout indefinitely. In nutritive solutions two 
or three promycelia may be produced. 


Schizonella . 1 

The spores are produced in series on the reproductive hyphae. 
At first two-chambered by means of a cross-septum, they later 
separate into two loosely-joined cells and form twin-spores ; each 
half germinates like an Ustilago- spore. 

Schizonella melanogramma (I). C.) (U.S. America). A 
species found on leaves of various species of Carex. The spores, 
when mature, escape by short fissures in 
the upper epidermis of the host ; they 
are black and coupled in pairs by a short 
connection. They germinate in water 
and produce a promycelium of three or 
four cells from which conidia are given 
off. In nutritive solution the promycelia 
produce conidia, which fall off and sprout 
yeast-like for a time. 


Tolyposporium. 

The sporogenous hyphae form tangled 
masses, and produce their spores firmly 
bound together in balls. The single 
spores are large, somewhat angular or 
spherical, and each germinates like, a 
spore of Ustilago. 



Tol^sporium junci (Schroet.) causes 


Fio. 165 . — Tolyposporium junci. 
Spore-mass. One spore has 
germinated and given off an 
eight-celled promycelium ; spori- 
dia are being abjointed in whorls. 
(After Woronin.) 


the formation of gall-like outgrowths on 
the ovaries, flower-stalks, and haulms of Juncus bufonius and 
J. capifatus. In these the spores are developed and escape as 
spore-balls. The spores, after a prolonged rest, germinate in 
water and produce four-celled promycelia, from which ovoid or 
spindle-shaped conidia are given off. In nutritive solutions many 
of the cells in each spore-ball germinate and produce promycelia, 
at first four-celled, later further divided by new septa; the 
conidia sprout and grow on till they reach the air, where aerial 
■conidia are formed. 

1 Schroeter, Biologie d. Pflaivzen, Bd. u. , 1877. 


306 


U ST I LAGINEAE. 


T. bullatum Schroet. (U.S. America). The ovaries of Panicum 
Crus-galli are transformed by this fungus into spherical tumour- 
like bodies, which project from the otherwise unchanged flower 
and enclose the black spore-masses. The spore-balls consist of 
hundreds of spores which, Brefeld says, germinate in water in 
the following year. Each produces one, two, or three two- 
celled promycelia, which give off terminal spindle-shaped conidia; 
these sprout in nutritive solutions and ultimately form aerial 
conidia. 

T. Cocconii Mor. In leaves of Carex recvrva in North Italy. 

T. penicillariae Bref. On Penicillaria spicata from Simla. 

T. cenchri Bref. On Cenchrus echinatus. 


Tilletia. 

Spores formed from hyphae, which swell up in a gelatinous 
manner. Conidia spindle-shaped or filamentous, and produced 
in whorls from the extremity of a non-septate promycelium ; 
they are developed only in air and generally fuse in pairs 
before being detached from the promycelium. 

Tilletia tritici (Byerk.) (T. curies Tub) (Britain and U.S. 
America). Smut, stink-brand or stinking-smut of wheat. 

This constitutes one of the most destructive smuts of wheat- 
grain, not only destroying the grains actually attacked, but the 
black spores cause such damage to the remainder, when threshed 
or ground, that it is useless for bread-making. The presence 
of this fungus is most obnoxious from its strong odour of herring- 
brine or trimethylamin, hence the name stinking-smut or stink- 
brand. The smut also possesses poisonous properties which make 
flour contaminated with it dangerous to human beings, and the 
straw or chaff injurious to cattle. 

Certain diseases are produced in animals by the consumption of smut- 
fungi with food. The effects of each species of smut have not as yet been 
closely investigated, but Tilletia tritici seems to be one of the chief causes 
of trouble. The following are also suspicious : Ustilago inaydis and the 
various species of Ustilago which attack oats, barley, wheat, and grasses. 
The symptoms in the few cases of disease observed do not agree very 
closely. A paralyzing effect on the centres of deglutition and the spinal 
cord seems to be regularly present. As a result one generally finds a 
continuous chewing movement of the jaws, and a flow of saliva, also 
lameness, staggering, and falling. Cattle, sheep, swine, and horses are all 
liable to attack. 


TILLETIA. 


307 


The black spore-powder is developed as an evil-smelling mass 
in the ovaries of the host, which are completely destroyed except 
the outer coats. As a rule every grain in an ear is attacked. 
The smut is at first oily or greasy, but gradually dries up to 
form a hard stony mass enclosed in the fruit-glumes and 




Fig. 1G6. — Tilletia tritici. 
Stinking -smut of Wheat. Ear of 
wheat with smut-grains indi- 
cated black. The isolated spike- 
let contains two smut-grains, 
which, as well as the isolated 
examples, show fissures in the 
original ovary wall. One smut- 
grain in section shows the in- 
terior filled with black spores, 
but the ovary wall still intact, 
(v. Tubeuf del.) 



Fig. IN .— Tilletia tritici. A, Two spores germinated in 
moist air ; a short promycelium is developed, and bears a 
crown of conidia (sporidia), several of which have fused in 
pairs. Fushion of conidia, germination, and development of 
a secondary conidium, C, are also shown. B, Two spores 
germinated in water with promycelia which elongate till the 
water surface is reached, where they form sporidia; the 
promycelia are septate and the plasma passes over into the 
younger cells, (v. Tubeuf del.) 


pales. The spores, therefore, do not escape as dust on the 
field, but remain in the heads and are garnered with the crop. 

Smutty ears are easily distinguished on the field by their 
stiff erect position towards harvest-time, as compared with the 
more or less nodding healthy ears ; their florets also lie more 
away from the axis of the ear, the chaff-glumes are more spread 


308 


USTILAGINKAE. 


out, and the grains are somewhat compressed. In earlier 
stages of development the diseased ears are less easily dis- 
tinguished, but they grow more rapidly than the normal, their 
ovaries are earlier formed, and have a dark greenish-brown 
colour. According to Kuhn, 1 the ears in their earlier stages, 
as they emerge from the leaf-sheath, possess abnormally thickened 
seed-coats, especially towards the apex, while in section they show 
a dark-green colour. He also found the grains to be replaced by 
a white and easily detachable mass of fine mycelium. Spores 
are formed as swellings on the ends of the sporogenous hyphae, 
and into these the plasma-contents of the hyphae pass over. The 
mature spores are dark-grey and spherical, with netted markings 
on the episporium. They germinate in water, and produce a 
promycelium of varying length. The conidia arise as a whorl 
of thread-like branches on the end of the promycelium, and into 
them all the protoplasm passes over, while the promycelium, 
after being cut off by a cross septum, disappears, leaving the 
conidia as isolated bodies (Fig. 167). The conidia become united 
in pairs, frequently before isolation. After fusion comes germina- 
tion, and the emission of a filament from the end of which 
sickle-shaped conidia are abjointed. Kuhn states that these 
conidia, as well as the whorled primary conidia, if placed in a 
damp atmosphere, can give rise to a hypha capable of infection. 
In water, however, the hyphae continue to grow longer, the 
plasma from the older parts passing over to the younger, and 
no conidia are formed (Fig. 167). 

The conidia which remain unpaired were found by Brefeld to 
behave similarly to those which pair, except that the resulting 
germ-tubes and conidia remained smaller. Spores refuse to 
germinate in nutritive solutions. Conidia grown in water 
cultures and placed afterwards in nutritive solutions, give off 
a fine mycelium, from which short, lateral, aerial branches 
become cut off by septa, and devote their contents to the pro- 
duction of a few sickle-shaped conidia : these are easily detached, 
and produce a mycelium capable of giving off further conidia 
in a manner similar to that just described. 

The investigations of Brefeld have also given the interesting 
result that hyphae which produce conidia may also give rise 
to spore-like bodies. The hyphae, after growth in length has 

1 Kuhn, Pie Kvanklteiten d. KnUnrijcinirhue, 1868. 


TILLETIA. 


309 


ceased, begin to thicken, at first equally, then more at some 
places than others, so that they become nodose or rosary-like, 
with swellings at irregular intervals. The. spores originate in 
the swellings, and between them are formed cross-septa which 
split and bring about isolation of the spores. 

Kuhn’s experiments on infection are of considerable interest. 
He investigated the germination of this and other smut-fungi, 
cultivating many of them in his garden at Halle, and published 
his results as early as 1858. 1 In his artificial infections he 
dusted seedlings with spores of Tilletia, and investigated the 
different parts of them microscopically. Sections showed him 
that the germ-tubes penetrate direct through the walls into 
the epidermal cells, and always in the neighbourhood of the 
lowest nodes. Thence the mycelium grows upwards with the 
lengthening plant, especially through the pith, and the plasma 
of the older mycelium passes onwards into younger parts. In 
this way the hyphae, without greatly disturbing the growth of 
the wheat-seedlings, reach the ovaries, and with the formation 
of spores begin the work of destruction. 

Kuhn was also able to demonstrate that both germinating 
sporidia and conidia are capable of infection, and that, where 
many had infected the same plant, so much mycelium could be 
produced that death of the host ensued. According to the 
same authority, the fungus attacks spring wheat more than 
winter wheat, and the common forms ( Triticum sativum and 
T. turgiduru ) with nearly allied varieties, more than “ spelt ” 
( Triticum spclta). 

As a preventive measure against Tilletia, the experiments of 
Kellermann, Swingle, Kirchner, and others, lead them to recom- 
mend Jensen’s method of placing the seed in hot water immedi- 
ately before sowing. (See Chap. YI.) 

Tilletia laevis Kuhn. (U.S. America.) This is another stink- 
ing smut of wheat similar to T. tritici, except that its spores 
have perfectly smooth coats. 

T. controversa Kuhn. Found in grains of Triticum repcns 
(couch-grass) as well as Tr. vulgare and Tr. glaucum. The 
spores are distinguished from those of T. tritici by the higher 
ridges and wider meshes on the episporium. The mycelium 

1 Previous to Kuhn, Prevost and Tulasne had in 1853 carried out experiments ; 
also Gleichen in 1781. 


310 


USTILAGINEAE. 


perennates in the rhizomes. The spores, according to Brefeld, 
germinate in water after a resting period of two years ; in 
two years more they lose their capacity for germination. 

T. secalis (Cord .) 1 is epidemic and destructive in ovaries of 

Secale cereale. 

T. decipiens Pers. (Britain). In fruits of Agrostis vulgaris 
and A. stolonifera. Schroeter says the plants remain stunted. 
Brefeld states that spores germinate in water after a resting- 
period of three years, and lose their capacity for germination 
in the following year. 

T. lolii Auersw. frequents the ovaries of cultivated Lolium 
perenne, and of L. temulenlum (darnel-grass). 

T. hordei Korn, occurs in grain of Hordeum fragile and //. murinum in 
Persia. 

T. separata (Kunze). In grain of Apera Spica-venti. 

T. calospora Pass. In grain of Andropogon agrestis in Italy. 

T. Rauwenhoffii Fisch. In grain of Holcus lanatvs in Belgium. 

T. olida (Riess.) forms stripes on the leaves of Brachypodium sylvaticum 
and B. pinnatum. 

T. sesleriae duel forms similar stripes on leaves of Sesleria coerulea. 

T. striiformis (Westend.) occurs on leaves, leaf-sheaths, and stalks of 
Alopecurus, Anthoxanthmm, Milium, Holcus, A rrhenatherum, Briza, Poa, 
Dactylis , Festuca, Bromus, Agrostis , Lolium, etc. (Britain and U.S. America). 

T. calamagrostidis Fuck. On leaves of Galamagrostis epigaea,C. //allerienia 
and Triticum repens. 

T. epiphylla Berk, et Br. Stink-brand of Australian maize. 

T. Fischeri Karst. In fruits of Carer cancscens in Finland. 

T. arctica Rostr. On leaves and stalks of Carex f estiva in Finmark. 

T. thlaspeos Beck. In fruit of T/daspi alpestre. 

T. zonata Bref. On Sporobolus ligidaris from Quito. 

T. (?) glomerulata Cocc. et Mor. occurs in Italy on leaves of Cynodon 
Dactylon, Plantago lanceolata, and Medicago. 

T. sphagni Nawaschin * was once regarded as a second form of spore of 
Sphagnum. 

T. oryzae Pat. The fungus to which this name was given forms 
sclerotia in the grain of Oryza saliva (Rice) in Japan. 

Brefeld 3 found that dark spores are given off from the surface of the 
sclerotia. These spores, on germination in nutritive solution, produced a 
septate mycelium which, in dilute solutions, gave off pear-shaped colour- 

' Kuhn, Hot an. Zeitung, 187(5, p. 470 . Cohn, Jahrbuch <1. Settles. Ges. f. 
raterland. Kuftur, 1876. Niessl, Hedwigia, 187(5. 

-Nawaschin, U C her die Hrandkrankhe.it <1. Torf moose, 1893; and Melanges 
hiologiques, t. XIII., liv. 3, 1893. 

:l Botan. Centralhlatt, iav. , 189(i, p. 97. 


TILLETIA. 


3U 


less conidia incapable of germination. When the nutritive solution was 
frequently renewed, the mycelium grew vigorously and formed a sclerotium- 
like body, from which the dark spores were laterally abjointed and set 
free. On this account Brefeld founded a group with the generic name of 
Ustilaginoidea ; it includes this species as Ustilaginoidea oryzae and an- 
other similar one on Setaria Crus-Ardeae he calls Ust. setariae. The group 
has affinities with the Ustilagineae and Ascomycetes like Claviceps, and 
Brefeld sees in it a connecting link between the two families. 

Several other American species of Tilletia have been recorded. 


Neovossia. 

Characters similar to Tilletia, except that the conidia produced 
on germination of the spores do not coalesce. Conidia sown 
in nutritive solutions produce a mycelium with two kinds of 
secondary conidia. 

N. moliniae Kornike. The black spore-powder is developed 
in enlarged ovaries of Molinia coerulea. The smooth ovoid 
spores are enclosed in a transparent mantle, and have a hyaline 
tail-like appendage. Each spore is produced at the end of a 
hyphal filament, which remains attached after the spore-mass is 
freed and forms the appendage. The spores germinate in water 
at once, and send up a simple aerial promycelium, on the apex 
of which a crown of many needle-like conidia are produced. 
Septation of the promycelia may take place if they become very 
long, the protoplasm passing into the apical segments and leaving 
the basal empty, as in Tilletia. Branching of the promycelia 
may also occur. The conidia on being shed give off sickle- 
shaped secondary conidia. In nutritive solutions, however, the 
conidia produce a mycelium from which either sickle-shaped or 
needle-shaped conidia may be given off, the latter however never 
as a crown or circlet. 

N. Barclayana Bref. In the fruits of Pennisetum triflorum in Simla. 
(This is not synonymous with Ustilago penniseli Babh.). 

N. (?) bambusae Bref. In fruits of bamboo from Brazil. 


Entyloma. 

Mycelium intercellular and never gelatinous. The spores 
are of intercalary origin, and arise here and there on any part 
of the mycelium. The spore-clusters appear externally as 
spots, and the spores never leave the host. The spores on 


312 


USTILAGINEAE. 


germination produce a thread-like promycelium bearing apical 
conidia, which conjugate in pairs before emerging from the 
host-tissues. 

The following species form conidia on the host-plant : 


Entyloma serotinum Schroet. occurs on leaves of Symphytum tuberosum , 
S. officinalis, and Iior ay o officinalis. 

E. canescens Schroet. On Myosotis (Britain). 


E. fuscum Schroet. On Papaver llhoeas and /'. Argemone. 

E. bicolor Zopf. On l’apaver llhoeas and P. dubium (Britain). 

E. ranunculi (Bon.) forms white spots on species of Ranunculus. Tufts 

of hvphae emerge from the stomata and 



Fin. 1*58 . — Entyloma calcndulat. a, My- 
celial filament, with two young resting- 
Bporea. 6, Resting -spore germinating ; 
the anterior pair of primary conidia 
shows conjugation or fusion at the base. 

Entyloma micro*porv.m. c t Germinat- 
ing resting-spore ; four primary conidia 
fusing in pairs at their apices. The 
same specimen seven hours later; com- 
mencement of abj unction of a secondary 
sporidium on each pair. (After De 
Bary.) 


form conidia, which on germination again 
give off conidia. 1 (Britain.) 

E. corydalis De Bary on Corydalis 
cava and C. solida. 

E. helos^fadii Magn. on He i 
nodiflorum. 

These do not produce conidia on 
the host-plant : 

E. thalictri Schroet. on Thalictrum 
minus (U.S. America). 

E. verruculosum Pass, on Ranunculus 

lanuginosus. 

E. Fischeri Thiira. on Stenactis bellidi- 
tfora. 

E. chrysosplenii (Berk, et Br.) on 

Ch rysosplen ium a I tern ifol in m ( Britain). 

E. linariae Schroet. on Linaria vulgaris 
(U.S. America). 

E. picridis Rostr. on /Yens hicracoides. 
E. eryngii(Omla ion Eryngium planum 


osc^a 


osc/adium 


and E. campestre. 

E. calendulae (Oudem.) on Ctdendula, Hicracium, Arnoseris, Arnica, 


Bel/idiastrum, etc. (Britain) (Fig. 108). 


E. crastophilum Sacc, on Pea and Dactylis in Italy. 


The following produce gall-like swellings : 

E. microsporum (Ung.) (E. Ungerianum De Bary) (Britain and 
U.S. America). On Ran unculus repens , R. bulbosus, and R. Ficaria 
(Fig. 168). 

E Aschersonii (Die) on roots of J/elichrysum arenarium (Fig. 16!l). 

E. Magnusii (t ie) on roots of Gnaphalium uliginositm and (l. lutco-album 
(Fig. 170). 


'll. M. Ward, Philo soph, transactions of Royal Soc. London. Vol. 178, 1SS9. 


ENTYLOMA. 


313 


Still to mention are : 

E. Ellissi Halst., known as “ white smut.” 1 It inhabits spinach 
(Spinacia oleracea), discolouring the leaves. 

E. ossifragi Eostr. on Narthecium ossifragum in Denmark. 

E. catenulatum Eostr. on Aira caespitosa in Denmark. 



Fig. 170 . — Entyloma Magnusii. Germin- 
ated spores ; the promycelium of one shows 
a whorl of three branches with apices 
elongating to form germ-tubes ; the other 
shows two, out of three, germ-tubes giving 
off branched sporidia (conidia). (After 
Woronin.) 


Fig. 169 . — Entyloma Asckersonii. Germin- 
ated spore with septate promycelium ; one 
promycelial branch remains rudimentary, 
the other (to left) has produced two branches, 
one of which has elongated and bears a coni- 
dium. (After Woronin.) 


E. leproidum Trab. 2 [ Oedomyces leproides (Sacc.)]. Diseased beet-root 
exhibits irregular outgrowths, which enclose spaces filled with the brown 
spore-powder of this fungus. 

E. nympheae (Cunningham) Setcli. 3 on various species of Nymphea in 
America, Africa, and Europe. 

Melanotaenium . 4 

Spores unicellular in patches on an intercellular mycelium 
lying deep in the host-plant ; they have a thick dark brown 

1 Halsted, New Jersey Agric. Exper. Station Bulletin, No. 70, 1890. 

2 Trabut, “ Sur une Ustilaginee parasite de la Betterave.” Compt. rend. 
cxviii., 1894. 

3 Setchell, Botanical Gazette, 1894, p. 18S (with illustrations). 

4 Schroeter, Kryptogam. Flora v. Schlesien. Woronin. Senckenberg Gesell, 1880. 


314 


USTILAGIX EAE. 


epispore, and the clusters appear black or leaden-grev. Ger- 
mination as in Entyloma. 

Melanotaenium endogenum (Unger) (Britain). This is 
found on Galium Molluyo and G. verum. The mycelium 
permeates the whole intercellular system of the host, and is 

nourished by large tufted haustoria. 
The host-plants remain small, with 
shortened internodes, shrunk leaves, 
and undeveloped flowers. The 
spores occur in patches in de- 
formed flowers, and on leaves and 
internodes. They are formed in 
summer, and by autumn are capable 
of germination in water ; Woronin 
could not keep them alive over 
winter. On germination a bifur- 
cate promycelium is produced, one 
branch of which remains rudimen- 
tary, while the other grows on, 
and, if long, becomes divided by 
cross-septa. At its apex, a number 
of conidia arise, and, after many of them have fused in pairs, 
they germinate directly to a septate filament into which the 
plasma passes over (Fig. 171). 

Mel. caulium (Schneider) causes the stem of Linaria vulgaris to swell 
up like a quill. 

Mel. cingens (Beck.) on Linaria genistifolia. According to Brefeld, 
this species only germinates after resting for four years, whereas Juel 
easily caused Mel. caulium to do so after a short rest. 

Urocystis. 

Spores massed into balls, consisting of several spores sur- 
rounded by smaller companion-cells incapable of germination. 
The central spores are clearly distinguished from the others 
by their larger size, darker colour, and thicker coat. The balls 
• if spores are developed inside coils of hyphae, which become 
entwined together and swell up in a gelatinous manner. The 
central spores on germination give rise to a pro mycelium, with 
terminal conidia which do not as a rule fuse in pairs, but grow 
out directly into mycelia. 



Fi<;. 171 . — Melanotaenium endogenum. 

Germinating spores. One has already 
produced a prornycelium with a whorl of 
five branches, of which two have fused. 
(After Woronin.) 


UROCYSTIS. 


315 


Urocystis occulta (Wallr.). (Britain and U.S. America.) This 
species is common on the haulms, leaves, leaf-sheaths, and less 
commonly on floral parts of Secede cereale (rye). It causes the 



Fig. 172. — Urocystis occulta on Rye. The ears are stunted, and the spore- 
powder emerges from longitudinal fissures in the upper part of the stems, 
(v. Tubeuf phot.) 


formation of grey stripes, from which a black spore-powder 
escapes. The haulms become diseased and smutty, thereby 
preventing development of the ear, which remains stunted and 


316 


USTILAGINEAE. 


empty (Fig. 172). Spore-formation causes the parenchyma of 
the stern to be destroyed in strips, along which rupture takes 
place, and the haulm, losing its rigidity, falls over. The balls 
of spores consist of one or two smooth spores enclosed by 
companion-cells. Germination takes place easily in water, and 
a circle of cylindrical conidia are produced from the end of 
each promycelium. The conidia, without becoming detached, 
give off a lateral germ-tube. The mycelium does not hibernate. 

While this smut does not occur on cereals so commonly as 
species of Ustilago and Tillctia, still it may sometimes cause 
severe loss. Treatment of seed by Jensen’s hot-water method, 
or by a copper sulphate steep, may be resorted to, but the 
results have not as yet been always successful. 

The only other smut of rye is Ustilago secalis in the grain, 
and it is only rarely found. Winter, however, considers rye 
amongst the host-plants of Urocystis ayropyri. 

Urocystis agropyri (Preuss.) (Britain and U.S. America). Leaves and 
liaulms of Triticum, repent, Arrhenatherum elatius, Festuca rubra , and 
Bromue inermis are the habitat of this species. 

U. festucae. Another species distinguished by Lie on Festuca. 

U. Ulei Magn. In leaves, more rarely in inflorescences, of Poa pratensis. 

U. luzulae Schroet. On leaves of Luzula pilosa. 

U. colchici (Schlecht.). On leaves of Colchicum autumnal. 
Muscari comosum, M. racemosum, Paris quadrifolia, and Sc ill a 
bifolia. (Britain and U.S. America.) 

U. cepulae Frost. 1 (U.S. America). Onion-smut. This 
frequents the green leaves and subterranean scales, producing 
pustules, which break when mature and allow the black spore- 
powder to escape. 

U. ornithogali Korn, frequents leaves of Ornithogalum umbellatnm. 

U. gladioli (Req.) is found in tubers and stems of Gladiolus (Britain). 

U. anemones (l’ers.). (Britain and U.S. America.) Anemone- 
snmt. This may be found in leaves or stems of many 
Ranunculaceae: Anemone Hepatiea, A. nemorosa, A. ranunculoides , 
Pulsatilla alpina , P. venialis, P. Pennsylvaniea, P. aeutiloba, P. 
baldensis, etc.; also on Atragenc alpina, Aconitum Leucoctonum, 
Aetaea spicata, Hellcborm viridis, H. niger, Panuneul us Fiearia, 
II. bulbosus, P. repens, R. sardous, Eranthis hiemalis. Brefeld 
says the spores germinate in water, after resting for half-a-yeur. 


R. Thaxter. Report of Connecticut Ayric. Ex/ur. Station for 1889. 


UROCYSTIS. 


317 


U. Leimbachii (Oertel.) causes globular swellings of the 
stem-base of Adonis aestivalis at Jena (Fig. 173). Patouillard 
regards this species as a form of U. anemones, differing somewhat 
on account of its underground habitat. 

U. sorosporioides Korn. (Britain). On Pulsatilla alpina, Thalic- 
trum minus, and T. foetidum, forming pustules and swellings. 



Fig. 173. — A , Urocystis anemones on Hellebore. Spore-patches on stalk and 
mid-rib. (v. Tubeuf del. ; specimen from Herr Schnabl of Munich.) 

B, Urocystis Leimbachii (U. anemones ), causing swelling at base of stem of Adonis 
aestivalis, (v. Tubeuf del.; specimen from Prof. Stahl of Jena.) 


U. violae (Sow.). (Britain and U.S. America.) The deforma- 
tions induced by this brand are not uncommon on Viola 
odorata in gardens, also on V. tricolor, V. badensis, and V. 
hirta. Its presence is shown externally by the marked thick- 
ening and malformation of leaf-petioles, runners, leaves, and 
fruit-stalks (Fig. 174). The swellings extend round the whole 
stem, and form pustular outgrowths on the leaves ; the black 
spore-masses appear after rupture of the epidermis. The 
flower may develop normally although other organs are diseased. 
In a case from the garden of Prof. Hartig, a flower-bud 
unfolded prematurely in the autumn, its stalk was very 
much deformed, the flower itself was somewhat stunted, yet 


318 


USTILAGINEAE. 


the plant as a whole did not seem to be much affected. On 
the other hand, a case was observed near Munich where a 
large plot of violets was completely killed out in a few years 
by this fungus. 

The anatomical changes induced on Viola odorata were 
investigated by Wakker 1 with the following results: a swelling 
of the stems, leaves, and flower-stalks occurred, often accom- 
panied by considerable twisting and rupture of the epidermis ; 
these changes were not caused by any enlargement of cells, but 



Fio. 174. — Urocy*ti* viola e on Viola. Smut-pustules are present on leaf stalks 
and fruit-stalks, accompanied by malformation, (v. Tubeuf phot.) 

the cambium remained longer active in the stem, and a secondary 
division of rind-parenchyma or mesophyll could be observed, 
along with a disappearance of intercellular spaces ; accessory 
vascular bundles were formed, but the secondary vessels remained 
incompletely developed. In short, new growth occurred, not 
in the earlier stages of the host’s life, but in the adult. 
Especially noteworthy is the formation of a small-celled tissue 
resulting from cell-division in the rind-parenchyma and the 
mesophyll ; this serves as a nutritive tissue for the fungus, 


1 Wakker, Primjsheinis Jahrhuch, 1892. 


UROCYSTIS. 


319 


and is destroyed during spore-formation, so that the balls of 
spores are found in large cavities in the host-tissue. 

In the spore-masses the enveloping companion-cells are more 
transparent than the spores proper. The latter germinate 1 easily 
in water, and produce promycelia which grow towards the air. 
On the extremities of these several conidia arise, and, without 
becoming detached, proceed at once to give off short eonidio- 
phores with terminal conidia. As this process is repeated 
indefinitely, chains of conidia are formed. Fusion of conidia 
never occurs. 

U. Kmetiana Magn. Magnus 2 describes this as destroying 
and filling with black spore-powder the ovaries of Viola tricolor 
(var. arvensis). 

U. filipendula Fuck, occurs particularly on petioles and leaf-ribs of 
Spiraea Filipendula. Brefeld found the spores germinating after a year. 
U. (?) italica (Sacc. et Speg.). In seed of Castanea vesca. 

U. purpurea Hazsl. Ovaries of Dianthus deltoides and I), prolifera in 

Hungary. 

U. (?) coralloides Rostr. In roots of Turritis glabra in Denmark. 

U. orobanches (Fr.). In roots of Orobanche. 

U. (?) monotropae (Fr.) In roots and stems of Monotropa in Belgium. 
U. Johansonii ( U . Junci. Lag.). In leaves of Juncus filiformis in 

Switzerland. 


Tuburcinia. 

Spores forming balls as in Urocystis, but all are equally 
capable of germination. The spore-aggregations form large or 
small, slightly thickened spots and crusts, which do not cause 
very marked deformation of the host. Germination results, as 
in Tilletia, in the formation of a promycelium bearing a tuft 
of conidia at one end. White conidia are also produced from 
the mycelium on the host-plant. 

Tuburcinia trientalis (Berk, et Br .) 3 (Britain and U.S. 
America). Plants of Trientalis europaea attacked by this fungus 
are conspicuous in early summer by their swollen dark-coloured 
stems and their smaller lighter leaves, which fall prematurely. 
The conidia appear as a white mould-like coating on the lower 

1 Prillieux, Bullet, de la Soc. botan. de France , 1880; and Brefeld (loc. cit.). 

Heft xn. 

2 Magnus, Naturforsch. Fr. d. Prov. Brandenburg , xxxi. 

3 Woronin, Senckenberg. naturforsch. Gesell., 1881. Plates I., II., III. 


320 


USTILAGINEAE. 


side of the leaf. The black spore-masses are formed in the 
rind-parenchyma, and sometimes in the pith ; they are set free 
by rupture of the epidermis. 

In autumn the symptoms are different. The plants appear 
normally developed, and have no coating of conidia ; dark 
swollen spots, however, appear on the leaves and leaf-petioles, 
in consequence of the massing of black spore-balls in the par- 
enchyma under the epidermis. 

The summer mycelium consists of colourless irregularly 
branched and slightly septate hyphae occupying the intercellular 



Fio. 178. — Apex of an isolated proray- 
eelium from Fig. 17.5 ; it carries a whorl of 
branches, some of which have fused in pairs; 
all are developing conidia. (After Woronin.) 


Fin. 175 . — Tuburcinia trientalit. Spore- 
mass germinating; several promycelia have 
been produced and are proceeding to form 
whorls of branches. (After Woronin.) 


Spore- 
a have 


Fio. 175. 


spaces of the pith and rind-parenchyma, also the vessels. The 
hyphae apply themselves closely to the cell-walls, and certain 
short branched hyphae actually penetrate into the cells. The 
spore-masses are developed from delicate branched multiseptate 
filaments of the vegetative mycelium. They begin as two or 
three little cells round which a coil of hyphae is formed ; the 
central cells, increasing in number and size, become a ball of 
dark smooth-coated spores, while the enveloping coil of hyphae 
disappears. 

The spores germinate during the same autumn, frequently 
in the position of their formation. A promycelium is first 
formed, and on its extremity a circlet of conidia arises ; there- 


TUBURCINIA. 


321 


after the promycelium becomes divided by cross-septa in its 
upper part, and the conidia too are frequently divided by one 
or two septa. The two promycelial cells become detached, 
while the conidia begin to fuse together by means of out- 
growths near their base ; thereafter each conidium gives 
out a secondary conidium, into which the plasma-contents 
pass over. A similar formation of secondary conidia may take 
place without previous fusion of the primary conidia. The 
conidia fall apart, and they, as well as the upper promycelial 
cells thereby left isolated, grow out as hyphae. It must be 
these hyphae which infect the rudimentary shoots of Trientalis 
when they are already partially formed for next year. The 
resulting mycelium permeates the shoots in the following spring, 
and branches of it emerge through the stomata, or pass between 
the epidermal cells and break the cuticle, to grow up either at 
once as conidiophores, or to form on the surface of the leaf a 
web from which conidiophores arise. The pear-shaped conidia 
are attached by their broader side, and easily fall off, leaving 
the conidiophores free to produce new conidia. The conidia 
are capable of immediate germination, and may produce a 
lateral germ-tube, which grows directly upwards, and gives off 
secondary conidia ; or the conidia themselves grow out into 
hyphae, capable, as Woronin proved experimentally, of carrying- 
out infection. Such hyphae penetrate between the walls of 
adjacent epidermal cells, and give rise to a mycelium which 
spreads in a centrifugal direction and forms the spore- 
masses. 

This same fungus has also been found on Euphrasia lutea 
and Paris quadrifolia. On Euphrasia , according to Winter, 
it causes formation of large swellings, accompanied by consider- 
able deformation of leaf and stem. 

T. primulicola (Magn.) Kuhn . 1 (Britain). This smut attacks 
flowers of Primula acaulis, P. officinalis, P. elatior, P. fcirinosa. 
In cases described in Germany, the blooms were generally 
attacked in the filaments or connective of the stamens, but also 
in the anthers, the ovaries, pistil, stigma, and sometimes in the 
calyx-tube ; while the whole flower-head was more or less 
discoloured by the black spore-dust. The mycelium permeates 

1 Magnus, Botan. Verein Brandenburg, 1S78. Kiilin, “die Entwickelungs- 
gesch. d. Primelbrandes,” Naturforsch. Gesell. zu Halle, 1892. 

X 


322 


USTILAGINEAK. 


the whole host and hibernates in the root-stock. The spores 
are developed from the ends of hyphae in the host-tissue, and 
are either isolated or joined into packets. They germinate 
easily in water, and produce either a fine germ-tube, or a 
thick promycelium with four oblong conidia on its apex. The 
eonidia are easily detached, and either develop to fine hyphae, 
or give off secondary conidia. Germination on the whole is 
similar to that of T. trientalis. Conidia may be also produced 
directly on the host-plant ; these were first described by Kuhn, 
who named them Paipalopsis Irmischiae ; later, however, he 
succeeded in infecting plants of Primula with the conidia, and 
in proving their relationship to this Tuburcinia. 

T. Cesatii Sorok. occurs on geraniums in liussia. 

Here, according to Setcliell, the following American genera should be 
placed : 

Burillia : B. pmtulata on Sagitlaria. 

Cornuella : C. lemnae on Lemna polyrkiza. 


Doassansia. 

Spore-masses consisting of numerous spores capable of ger- 
mination, enclosed in a layer of sterile cells. The latter are 
most conspicuous in the species frequenting aquatic plants, and 
are filled with air, — Brefeld regards them as swimming-organs. 
The spore-masses lie in groups embedded in the host-plant. 
The species inhabit plants with an aquatic or moist habitat, 
and produce on them leaf-spots with black pustules. 

Fisch 1 investigated the life-history of Doassansia sagittariae. 
He found an intercellular mycelium which, inside the stomata, 
formed sporocarps, consisting of sclerotium-like coils of hyphae 
enclosing several cells which form spores. The spores on germina- 
tion give rise to promycelia, which produce sporidia in a manner 
similar to Entyloma. The sporidia easily germinate in water, 
and can immediately infect young leaves. The germ-tubes 
creep on the surface of leaves, and attaching themselves by 
an adhesion-disc over the wall between two adjacent epidermal 
cells, they penetrate this wall. The hypha, while passing 

1 C. Fisch., Ber. </. deutnch. hotan. Gexell . , 1S84, p. 405. Cornu, Alina/. </. sci. 
natur. XV., 1883. Setcliell (Botanical Gazette, 1 Sl>4 ) records the American 
species and comments on them. 


DOASSANSIA. 


323 


through the wall, remains thin, but on emerging into an inter- 
cellular space it soon thickens and branches into a mycelium. 
Infection results in the appearance of yellow spots, clue to 
rapid destruction of the chlorophyll and death of cell-contents. 
Experiments in germination have been carried out by Setchell 
and Brefeld . 1 

Doassansia sagittariae (West.) (Britain and U.S. America). 
In leaves of Sagittaria. The spores, according to Brefeld, 
germinate in water, after hibernation. They produce unicellular 
promycelia with a terminal tuft of more or less spindle-shaped 
conidia, which at once begin to sprout and fall off. On the 
surface of a nutritive solution they continue to sprout yeast- 
like, and form close mouldy coatings. ( Doassansia is the only 
genus of the Tilletiae in which Brefeld found yeast-like sprout- 
ing of conidia.) 

D. alismatis (Xees) (Britain and U.S. America). This 
inhabits leaves of Alisma Plantcigo and A. natans, producing 
knotty swellings. The spores are enclosed in a layer of com- 
panion-cells containing air, whereby the masses swim on water. 
On the promycelium the conidia arise from tufts of conidio- 
phores ; they fuse in pairs, and secondary conidia are developed 
from each pair or even from single conidia. 

D. Niesslii (de Toni) forms small spots on leaves of Buto- 
mus umbellatus. The spores are surrounded by companion-cells 
containing air. They germinate before leaving the spore-patch, 
and produce conidia, even secondary conidia, before rupture of 
the host-epidermis takes place. Brefeld describes the spores 
as germinating in water to form a very short promycelium 
with short thick conidia which fuse in pairs and give off larger 
secondary conidia from their apices. In nutritive solution 
conidia are developed, which give off septate filaments whence 
further conidia arise. Aerial conidia are ultimately developed. 

Ma gnus found that the spores of I). alismatis, D. Niesslii, 
and other species germinated at once on reaching maturity. 
Brefeld, however, found that this took place only after they 
had lain over winter. It may be that here, as with some 
higher plants ( e.g . Pinus Cembra), there is an immediate 
capability of germination, but also a deferred, the latter requiring 

1 Setchell, Annals of Botany, vi., 1892. Brefeld, Schimmelpilze, Heft xn., 

1895. 


324 


USTILAGINEAE. 


to be preceded by a considerable resting-period, during which 
germination will not take place. 

D. Martianoffiana (Thiim.). In leaves of Potamogeton natans and /'. 
grammem. 

D. occulta (Hoffm.). In fruits of species of Polamogeton. 

D. intermedia (Setch.). An American species found on leaves of 
Sagitturia variabilin. 

D. comari (Berk.). In leaves of Comarum palustre in Britain. 

D. limosellae (Kunze.). In flowers of Limosella aquatica. 

D. hottoniae (Rostr.). In leaves of Ilottonia palustris in Denmark. 


Thecaphora. 

Spores, large, spherical, and inseparably united into packets 
of several spores. Germination results in the formation of a 



Fig. 177 . — Thecaphora hyalina. Pluricellu* 
lar Hporc, with two cells (spores) germinating. 
(After Woronin.) 



Firs. 178. — Sorosjjorium saponariat (var. 
Lychnidis dioicae,) Mature spore-mass, and 
H|M>res germinating. (After Woronin.) 


promycelium from the apex of which a single conidium is 
produced. 

Thecaphora lathyri Kuhn. Spore-balls formed in the seeds 
of Lathyrus jrratensis, and escaping as a brown powder on 
dehiscence of the pods. The spores germinate in water with 
formation of a promycelium bearing a single apical conidium, 
which produces a hypha, but never secondary conidia. In 
nutritive solutions the spores produce a mycelium from which 
conidia are continuously given off. 

Th. hyalina Fingerh. (Britain). This occurs in fruits of 
species of Convolvulus. Woronin describes the spores as having 
germ-pores through which a septate germ-tube is emitted ; the 
individual cells of the germ-tubes develop into hyphae, without 
formation of conidia. 

Th. affinis Scluieid. In fruits of Astragalus glycyphyllus (l T .S. America). 

Th. Trailii Cooke. In flowers of Car duns heterophyllus in Scotland. 


THECAPHORA. 


325 


Th. Westendorpii Fisch. In Lolium perenne in Belgium. 

Th. pimpinellae Juel. In fruits of Pimpinella Saxifraga in Sweden. 
Th. aurantiaca Fingh. In leaves of Urtica dioica. 

Th. pallescens Fingh. In leaves of Fragaria collina. 


Sorosporium. 

Spore-formation takes place in a mass of twisted gelatinous 
hyphae. Spores at first embedded in a gelatinous investment 
and united into packets, but later becoming separate. Promy- 
celium filiform and septate. 

Sorosporium saponariae Eud. This causes deformation of 
flowers of Diantlius deltoides, Saponciria officinalis, Silene inflata, 
and S. vclutina, Stcllaria Holosteum, Cerastium arvense, Lychnis 
dioica, and Diantlius prolifer. 

S. dianthi Rabh, on Diantlius prolifer, is probably identical with the 
preceding species. 

We append here as doubtful Ustilagineae, the genera Graphiola 
Schinzia (Entorrhiza), Tvbcrcidina, and Schroeteria. 

Graphiola. 

The sporocarps of this genus are formed on the surface of 
plant-organs containing mycelium ; they are little spherical 
structures enclosed in a peridium, and contain filamentous 
septate liyphae. The hyphae may be sterile or fertile ; the 
spores are produced on lateral cells of the fertile hyphae. 
From the germinating spores, either a thread-like mycelium or 
spindle-shaped conidia arise. 

Graphiola phoenicis Pait. 1 (Britain.) This fungus is a 
parasite on leaves of palms ( e.g . Phoenix dadylifera and 
Chamcrops humilis ) in the open in Italy and other Mediter- 
ranean countries, in hot-houses elsewhere. The sporocarps make 
their appearance as little black protuberances on both sides of 
the leaf. The mycelium forms a close hyphal tissue, which 
encloses and kills parenchymatous cells, displaces the bundles 
of sclerenchyma, and ruptures epidermis and hypoderm. De- 
formation is, however, localized to these spots. 

1 Ed. Fischer, “ Beitrag z. Kenntniss d. Gattung Graphiola ,” Botan. Zeitung, 

1883. 


326 


USTILAGINEAE. 


The sporocarps consist of a two-layered peridium, a sporogenous 
layer, and tufts of sterile hyphae. The outer layer of the 
peridium forms the outer layer of the black protuberances on 
the leaves ; the inner layer is delicate. The sporogenous hyphae 
originate from the centre of the underlying hyphal tissue, and 
form a palisade-like layer in the bottom of the sporocarp cavity, 
the remaining space being filled with spores and tufts of barren 
hyphae. These latter hyphae rise amongst the sporogenous 
ones, and project as a fine brush-like tuft out of the ruptured 
peridium. The sporogenous hyphae grow vertically upwards, 
and become septate, forming chains of loosely united, roundish, 
hyaline cells or joints. The terminal joiuts give off several 
spherical cells laterally, and die away, leaving the cells loose 
in the sporocarp cavity. From division of the spherical cells 
yellow spores result, and, on rupture of the peridium, are 
carried out on the tufts of sterile hyphae to be scattered by 
wind. The spores germinate in water, and produce either a 
promycelium or conidia. 

Gr. congesta Berk, et Eav. occurs on leaves of Chamerops 

Palmetto. 


Schinzia (Entorrhiza). : 

Spores produced on the ends of lateral branches of a mycelium 
in the cortical cells of the root of the host-plant. Germina- 
tion results in production of a simple or branched sporophore 
(promycelium), from which kidney -shaped conidia (sporidia) are 
produced. 

Schinzia cypericola Magn. This causes deformation of (lie 

roots of Cyperus flavescens (Fig. 170). 

Sch. Aschersoniana Magn. causes swellings oil the roots of June us 
bufonius [Britain]. 

Sch. Casparyana Magn. In roots of Juncus Tenageut. 

Sch. digitata Lagerh. In roots of Juncus articulatus. 

Sch. (Naegelia) cellulicola Naeg. In roots of Iris in Switzerland. 

Sch. (Entorrhiza) solani Faut.- [This is given as the cause of a disease 
on potato. The plants droop and ultimately rot at the neck, the leaves 
become yellow, and neither flowers nor tubers are produced.] (Edit.) 

1 P. MagnuB, at Botan. Verein d. Prov. Brandenburg, 1X7S; “ Ueber oblige 
Arten d. (tattling Schinzia,'' B*r. </. iltnlsch. botan. tbs., 18SS, p. 100 ; ('. Weber, 
liotan. Zeituwj, 18S4. 

2 Fautrey, /{erne mycolog., 1896, p. II. 


TUBERCULINA. 


327 


Tuberculina. 

Mycelium parasitic on hyphae and spore-patches of Uredineae. 
Short rod-like hyphae spring from the spore-patches, and give 
off from their apices, globose conidia, which on germination 
produce branched promycelia bearing sickle-shaped conidia. 



Fig. 179. — Schinzia cypericola on Cyperus Jlove scene. Several roots show palmately- 
divided swellings. Isolated spore. (After Magnus.) 


Tuberculina persicina Ditni. The lilac-coloured spores are 
found on aecidia of Peridermium pini and other aecidial forms, 
also on some species of Caeoma } (Britain and U.S. America.) 


1 Plowright (British Ustilagineae) gives also Aec. asperifolii, Aec. tussilaginis y 
arul Roestelia lacerata as hosts. 


328 


USTILAGINEAE. 


T. maxima Kostr. Occurs on rust-patches on Weymouth 
pine. It lias larger spores than the preceding species. 

Schroeteria . 1 

Spores joined in pairs, rarely in threes, with their broad 
faces together. They are developed from single joints of a 
septate non-gelatinous mycelium, particularly from short curled 
lateral hyphae. Spherical conidia are produced, like those of 
Pcnicillium, by intercalary growth in chains from the end of a 
•conidiophore which is generally unbranched. 

Schroeteria Delastrina (Tul.) occurs in seeds of Veronica 
■arvensis, V. hederifolia, V. triphylla, and V. praecox. The spores 
germinate in water, and produce conidia incapable of further de- 
velopment, even when transferred to a nutritive solution. In such, 
however, spore-germination is more vigorous, and an abundant 
mycelium results, but it seems to be unable to produce conidia. 

Sch. Decaisneana (Bond.). In seeds of Veronica hederifolia at Paris. 


UREDINEAE. 

The Uredineae or Rust-fungi possess several forms of spores, 
one of which, the teleutospore, is rarely, if ever, absent from 
the life-cycle of any species. The teleutospores consist of one, 
two, or more cells enclosed in a thick coat of dark colour, and 
thereby well adapted to carry the fungus over winter. When 
germination occurs, each cell of a teleutospore gives off a germ- 
tube through a pore or thinner place in its wall, and from 
this a promycelium 2 is formed, consisting as a rule of four 
cells. Each teleutospore originates from a sporophore of its 
own, and in the course of development two nuclei, originally 
present in each cell of the young teleutospore, fuse together. 
When germination takes place, and the promycelium is formed, 
the single cell-nucleus, derived as above, divides into two, then 
into four, so that a nucleus is produced for each of the cells 
of the promycelium. From the promycelium four sterigmata 
are given off, and each produces a single sporidium . 2 These 

1 Brefeld regards the species as forms of higher fungi, not as Ustilagineae (Heft 
xti., p. 204). 

2 Brefeld considers that the promycelium and sporidium are respectively a 
baaidium and a basidiospore. 


UREDINEAE. 


329 


sporidia on germination give infecting mycelial byphae. In 
the case of Colcosporium, the promycelium is formed inside the 
teleutospore in a manner similar to the Protobasidiomycetes. 

Besides teleutospores, there occur uredospores. These are 
given off from patches or sori throughout the summer till 
autumn, when they are followed by teleutospores on the same 
sori. The uredospores somewhat resemble the teleutospores, 
but generally consist of one cell only with a thinner coat of 
lighter colour ; they either germinate at once without a resting 
period, and give rise to a germ-tube capable of direct infection 
of new hosts ; or less frequently they are resting-spores for 
a time. 

A third form of spore occurring in the life-history of the 
Uredineae is the aecidiospore, produced in a special structure, 
the aecidium. The aecidium is developed inside the leaves or 
other organs of the host-plant, and when mature ruptures the 
overlying epidermis ; it lias as a basis a firm hyphal tissue, 
the upper surface of which becomes a disc of short erect sporo- 
phores. From each sporophore there is formed by intercalary 
growth a chain of cells consisting alternately of spores and 
smaller intermediate cells, which do not become spores. The 
youngest cells in an aecidium are those next the sporophore- 
disc, and they are forced outwards by intercalation of younger 
cells between them and the disc. The cells so produced 
become alternately intermediate cells and spores ; the former 
increase for a time, then decrease and disappear, the spores 
however continue to increase in size as the chain grows forward 
and to take on the characters of the mature aecidiospore till 
they are finally shed from the aecidium. The production and 
distribution of aecidiospores may thus go on continuously for 
a considerable time. The sporophores at the periphery of the 
disc do not however produce spores ; chains of cells are also 
produced from them by intercalary growth, but the cells are of 
equal size, and remain closely connected with their neighbours, 
so as to form a membranous covering over the spore-sorus, 
this is the so-called peridium, on rupture of which the aecidio- 
spores escape. In many Uredineae the peridium is suppressed 
( Ccieoma ) ; in others ( Phragmidium ) it is replaced by other 
structures, the paraphyses. The spores of the genus Eadophyllum 
are produced in series in aecidia enclosed by a peridium, but in 


330 


UREDINEAE. 


germination they behave more like typical teleutospores than 
aecidiospores. 

Before the relationship of these various forms of spores was 
known, Aecidium and Caeoma were regarded as independent 
groups, and named as such ; even yet many isolated forms of 
uredospores, teleutospores, and aecidiospores are known, the 
relationships of which are quite obscure. 

The aecidia are always preceded or accompanied by a further 
form of spore produced in a special structure of its own. These 
spores have hitherto been called spermatia, and their sporocarps 
spermogonia, on the assumption that they were male organs. 
Now, however, many of them are known to be capable of 
germination in artificial nutritive solutions, hence they are more 
probably a form of asexual bud, and better named conidia, 
their sporocarps pycnidia. The pycnidia are Mask-shaped 
structures sunk in the tissue of the host, with a pore or 
mouth emerging through the host-epidermis ; they generally 
occur in leaves, and occupy the upper epidermis, the aecidia 
occurring on the lower. From the mouth of the pycnidium 
there frequently emerges a tuft of fine filaments, outgrowths 
from the inner wall of the Mask. The pycnidia possess a lively 
colour and flowery odour, hence it has been suggested that 
the conidia may be distributed by insects; but they do not 
appear to be able to germinate in the open, and infection- 
experiments with them have never as yet succeeded. On this 
account they are regarded as degenerate structures. 1 

The various forms of spores are also distinguishable by the 
manner in which they bring about infection. Teleutospores on 
germination produce sporidia, which pierce the membranes of the 
prospective host at a spot where two adjoining cells are in 
contact, and thus make their way into the intercellular spaces. 
Uredospores and aecidiospores, however, first seek a stoma and 
enter the intercellular spaces of the host through it. 

The following different forms of Uredineae exist: (1) Those 
which possess teleutospores alone, c.g. C/i rysom y.ra abictis ; (2) 
those with teleutospores and uredospores, c.g. Puccinui pruin 
spinosae ; (3) those with all the forms of spores, c.g. Pitcnma 
gra minis : (4) those without uredospores, r.g. Gym nosporangi u m . 

1 Rat hay, “ Untersuchungeu tiher ilie Spermogonien il. Rostpilze, Dfukxrhr\fl 
d. Wiener A kail. 1 1. Wiwenxch. , 1S83. 


UREDINEAE. 


331 


The different forms of spore may be found on one and the same 
host-plant (autoecious Uredineae), or the aecidiospores and 
pycnidial conidia may frequent a different host from the uredo 
and teleutospore-forms (heteroecious Uredineae ). 1 

A mycelium may be produced from the germinating aecidio- 
spores, uredospores, or sporidia. It spreads throughout the 
intercellular spaces of attacked organs and causes thickening, 
distortion of the tissues of its host, or the formation of “ witches’ 
brooms.” Nutriment is frequently obtained by means of cone- 
shaped or button-like haustoria in the interior of host-cells. 

Hibernation of rust-fungus is most commonly attained through 
the teleutospores, the thick coats of which make them peculiarly 
suited to pass through a lengthened resting- period. Some forms, 
however, hibernate by uredospores, by aecidiospores, or by the 
mycelium remaining on or in living perennating stems, twigs, or 
underground rootstocks of their host. 

Aecidiospores on germination produce, as a rule, a mycelium 
which gives rise to uredo- or teleutospores, rarely to aecidiospores 
(e.g. Puccinia senecionis and Uromyces ervi ). 2 Uredospores on 
germination, produce a mycelium from which uredospores are 
first given off, then teleutospores. The sporidia of teleutospores 
give rise to a mycelium which frequently produces pycnidia 
and aecidia. In rare cases, the sporidia of species, which normally 
form aecidia, are said to develop a uredo-mycelium (e.g. Pucc. 
graminis according to Plowright). 

The Uredineae are for the most part strict parasites, and 
exhibit marked adaptation to their respective host-plants. Several 
of the polyxenous members frequenting several species of host- 
plant have been found to vary according to their habitat, so that 
one and the same species assumes a slightly different form on each 

1 The phenomenon of heteroecism was till quite recently known only amongst 
the Uredineae. Woronin and Nawaschin have, however, recently pointed out that 
it exists in Sclerotinia ledi, one of the Ascomycetes (p. 277). The conidia of 
this species are produced only on Vaccinium uliginosum, the apothecia only on 
Ledum, and alternate with each other, so that the Ledum can be infected only 
by germinating conidia, the Vaccinium by germinating ascospores. 

2 Dietel { Naturforsch. Verein in Vienna, 1S94) pointed out further cases of 
this kind, in which aecidia were produced the summer through, and no 
uredospores, while in autumn teleutospores were formed. He has more recently 
stated the general conclusion (Flora, 1895, p. 394) ; that with these species of 
Uromyces and Puccinia, which produce aecidia and teleutospores, but no uredo- 
spores, the aecidiospores are capable of reproducing aecidia when no perennating 
mycelium is present. Similarly with those few species which produce a very 
small number of uredospores. 


332 


UREDINEAE. 


host-species. I have previously shown, 1 with regard to the 
mistletoe ( Viscum album), that the different forms on Pinus, 
Abies, and various broad-leaved trees, which some authors regard 
as distinct species, might ecpially well be regarded as forms of 
one species differing slightly on account of their different 
substrata. Magnus 2 designates as “habitat-races” these forms 
of heteroecious Uredineae whose aecidial generation has become 
adapted in some varying degree to each of their respective 
species of host-plant. Thus the various forms of Aecidium 
eonvallariae, on its different host-plants, he regards as forms of one 
and the same fungus, the Puccinia of which occurs on Phalaris 
arunclinacea. 

The manner in which such adaptations originate is indicated 
by my experiments with Gymnosporangium. Thus G. clavariae- 
forme can infect leaves of Crataegus and produce aecidia 
without failure ; whereas the same infection carried out on 
Sorbu8 and Cgdonia results in incomplete development of aecidia 
(see Table, p. 385). In this way there might easily be pro- 
duced one form which infected Crataegus, and another confined 
to Cgdonia. The same thing occurs with the various Pcridermia 
of pine-needles ; these, according to the investigations of 
Klebahn, are caused by one or other species of Coleosponum 
from very different species of host-plant. 3 

The best examples of all, however, are presented by the 
cereal-rusts, as demonstrated by Eriksson. This investigator 
believes that the forms distinguished by him as “specialized 
forms ” (by Rostrup as “ biological species or varieties ”) are 
of common origin. In course of time these have taken on 
different biological characteristics in adapting themselves to 
the varied nature of their substrata, their various host-plants, 
so that in many cases they can no longer suit themselves 
to the host-plant of the original parental form. In fact, species 
were found with aecidia of similar shape when occurring on 
the same host-plant, yet completely specialized from the aecidia 
on another host. They thus present a stage intermediate to 
that of the “ habitat- races ” just mentioned. 

1 v. Tubeuf, Hot an. CentralMatt, xi„, 1389, p. 312. 

- Hedwitjia, 13*14, p. 77, and 1S9.">. 

•' Klebahn’s views on this subject, along with further investigations on other 
fungi, will he found in Zcituchvift f. Pflan:>nhankh> i(tni, 1893, p. 153. 


UREDINEAE. 


333 


The european Uredineae comprise the following families and 
genera : Tuceinieae • ( Uromyces and P actinia ) ; Phragmidieae 
( Triphragmium and Phragmidium) ; Melampsoreae ( Mclampsora , 
Melampsorella, Calyptospora, Coleosporium, Chrysomyxa, and Gron- 
artium) ; Gymnosporangieae ( Gymnosporangium ) ; Endophylleae 
(Endophyllurn) ; also the genus Uredinopsis on Ferns. 

Uromyces. 

Teleutospores unicellular and produced in flattened sori. 
Only one teleutospore is abjointed from each sporophore. 
Teleutospores with a single germ-pore. Uredospores, aecidia, 
and pycnidia are not present in every species. 

(1) All forms of spore present on the same host-plant: 

Uromyces ervi (Wallr.) (Britain). 1 Vetch-rust. The aecidia 
are produced on Vicia hirsuta in May and throughout the 
summer. Scattered amongst the aecidia are the sori from 
which uredospores are sparingly given off in early summer ; 
the teleutospores are given off abundantly from the same 
sori from July onwards. The aecidiospores germinate on the 
vetch plants, and produce therein a mycelium from which the 
aecidia and teleutospores arise. Infection by means of sporidia, 
derived from the teleutospores, results in the production of a 
mycelium which bears aecidia only. Pycnidia (spermogonia) 
are absent in this species and also in V. fabae. 

U. fabae (Pers.), [ U. orobi (Pers.)] (Britain and U.S. America). 
This occurs on species of Vicia and Lccthyrus. Sori are formed 
abundantly and give off both uredospores and teleutospores — - 
the latter being smooth-coated. No pycnidia have as yet been 
observed. 

U. trifolii (Hedw.). Clover-rust. Parasitic on various species 
of clover. Uredo- and teleutospores are generally produced ; 
aecidia have been found only on Trifolium repens (Germany and 
Britain), T. incarnatum (Italy), T. pratense (Denmark, Britain, 
and America). On Trifolium repens both teleutospore and 
aecidium generations cause swelling and distortion of leaf-ribs 
and petioles, the deformation being most marked where the 
mycelium has hibernated and produced teleutospores in spring. 

1 The chief authorities used for the occurrence of the Uredineae in Britain 
and North America are Plowright (British Uredineae, 1889), and Farlow and 
Seymour (Host-Index for U.S. America, 1891). (Edit.) 


334 


UREDINEAE. 


U. appendiculatus (Pers.), [ U . phaseoli (Pers.)]. On species 
of Phaseolns. (Britain and U.S. America.) 1 

U. primulae Lev. On Primula hirsuta. 

U. limonii (I). C.). On Armeria and Statice. (Britain and 
U.S. America.) 

U. polygoni (Pers.). On Polygonum and Pumcx. (Britain 
and U.S. America.) 

U. acetosae Schroet. On Rumex. 

U. silenes (Schlecht.). On Silene and Dianthus. 

U- euphorbiae (Schwein.). On Euphorbia Preslii in Italy, 
and some other species in America. 2 

U. geranii (D. C.). On Geraniums. (Britain and U.S. America.) 

U. betae (Pers.). On Mangel Wurzel and Beta. (Britain 
and U.S. America.) 

U. parnassiae (D. C.). (Britain.) 

U. salicorniae (O. C.). (Britain.) 

U. valerianae (Schum.). On Valeriana dioica (Britain). 

(2) Pycnidia ( spermoyonia ) and aecidia produced on one host; the 
related uredo- and teleutospores on another host : 

Uromyces pisi (Pers.) (Britain) Pea-rust. The uredospores 
and teleutospores are developed in various species of Pisum, 
Lathyrus, and Vicia. The teleutospores are finely punctured. 
The aecidia appear on the under surface of the leaf of Euphorbia 
Cyparissias, and are preceded by pycnidia. 

Attacked plants of Euphorbia become completely changed in 
their appearance. The stems are much elongated, and as a 
rule remain unbranched. Flowers are seldom or never produced ; 
if so, they are permeated by mycelium and deformed. The 
leaves are short, thick, and rounded-off ; they have a pale-green 
colour, and are distant from each other on the shoot. Their 
internal structure is also considerably modified. Wakker states 
that the cells of the mesophyll become enlarged, while no 
collenchyma is developed in the ribs. Fentzling 8 gives the 
following changes : the epidermal cells become broader ; stomata 
are more numerous on the upper surface of the leaf, and fewer 
on the lower ; the laticiferous tubes below the upper leaf- 

1 Description, illustration, and treatment in N. York At/ric. Exptr. Station. 

Bull., 4S, 1 89*2. 

2 Magnus, Berichte d. deutuch. botan. Gts., 1S9.S. 

3 “ Untersuchung d. Veriinderungen welche (lurch Rostpilze hervorgerufen 
werden.” Inaugural Dissertation. Freiburg, 1S92. 


UKOMYCES. 


335 


epidermis are reduced in number : intercellular spaces are formed 
in the normally compact palisade parenchyma, and its cells 
become shorter and broader, while those of the spongy paren- 
chyma are increased both in size and number ; the fibro-vascular 
bundles remain unchanged, although the cells surrounding them 
may be more or less abnormal. Where thickening of the stem 
takes place, it is chiefly due to multiplication of the cells of 



Fig. ISO . — Uromyces pisi. Comparison of healthy flowering plant of Euphorbia i 
Cyparissias, with a much-elongated, non-flowering plant bearing aecidia of Pea- 
rust. (v. Tubeuf phot.) 


cortex and pith, while at the same time those of the cortical 
parenchyma become somewhat enlarged and altered in shape ; 
the woody portion is less developed than normally ; and 
laticiferous tubes are neither so large nor so conspicuous as 

usual. 

The aecidia of this species are found only on the lower 
surface of the leaf ; they are saucer-shaped, and have a broad 
lobed white margin. 



336 


UREDINEAE. 


As a preventive measure, it would be advisable to keep 
down spurge-plants near fields or gardens where peas are likely 
to be attacked. 

U. striatus Schroet. (U. S. America). U redo- and teleutospores 
on species of Lotus, Medicago, Trifolium, and sometimes Vicia. 
Pycnidia and aecidia are produced on Euphorbia Cyparissias ; 
the mycelium induces changes in the tissues similar to the 
preceding species, but the Euphorbia remains stunted instead 
of elongating as in attacks of U. pisi, 

U. dactylidis Otth. Uredo- and teleutospores on species of 
Poa, Dactylis, Arena, and Brachypodium. Aecidia on several 
species of Homunculus (not on II. Ficaria). (Britain and U.S. 
America.) 

U. poae Rabh. Uredo- and teleutospores on Boa-, Aecidia 
on Ranunculus Ficaria % II. bulbosus, and It. repens. (Britain). 

U. lineolatus Desm. ( U . maritimus Plowr.). 1 Uredo- and 
teleutospores on Scirpus maritimus. Aecidial forms = Aecidium 
sii latifolii on Siam and Arc. liippuridis on Hippuris, also a 
form on Glaum maritima in Britain. 

U. junci Desm. Uredo- and teleutospores on species of Juncus. 
Aecidia on Pidicaria. (Britain and U.S. America.) 

(3) Only uredospores und teleutospores known ; they frequent 
the same host. 

Uromyces caryophyllinus (Schrank.) 2 Carnation Rust. [This 
attacks carnations at all stages of growth. The mycelium extends 
inside the plant and forms spore patches which rupture the 
epidermis. Uredospores are produced first, then the teleuto- 
spores ; the former germinate at once, the latter only after a 
resting-period. The use of sprays of potassium sulphide or 
copper sulphate, and the cultivation of hardy varieties have been 
recommended.] (Edit.) 

Uromyces scutellatus (Schrank.). On species of Euphorbia. 
The mycelium is perennial in the root-stock and permeates the 
whole plant. Teleutospores developed in dark-brown spots on 
the under surface of leaves. Diseased stems are generally un- 
branched, and carry only small leaves and no flowers. 

1 Plowright, Gardener's Chronicle, IS!)U. 

2 Hoisted, X. Jersey Agric. Coll. Exper. Station Report, 1801. Atkinson, 
“Carnation Diseases, - ’ American Carnation Sor. ; with Illustrations. X. York 
Agric. Exper. Station Bulletin, 18110. 


UROMYCES. 


337 


U. tuberculatus Fuck. On Euphorbia exigua. 

U. proeminens Duby. On species of Euphorbia. 

U. sparsus (Kunze et Schm.). On Spergularia , and Stellaria (Britain). 
U. Schroeteri De Toni. On Lychnis and Silene. 

U. cristatus Schroet. et Niessl. On Viscaria and Dianthus. 

U. ficariae (Sebum.). On Ranunculus Eicaria (Britain and U.S. 

America). 

U. astragali (Opiz). On Astragalus (U.S. America). 

U. genistae (Pers). On Genista, Cytisus, Colutea, Galega, Caragana, 

Onnbrychis, etc. 

' U. anthyllidis (Grev.). On Anthyllis and Lupinus (Britain). 

U. lupini Sacc. On Lupinus (U.S. America). 

U. trigonellae Pat. On leaves of Trigonella Foenum-graecurn in France. 
U glycyrrhizae Babb. On Glycyrrhiza. 

U. cacaliae (D. C.). On Adenostyles and Cacalia. 

U. rumicis (Sebum.). On Rumex (Britain). 

U. alpinus (Schroet.). On Rumex alpinus. Magnus 1 has recently sep- 
arated this as the single species of a new genus Schroeteriaster, allied to 
Uromyces and Puccinia. The uredospores arise from patches of sterigmata 
without peridia or paraphyses ; they are unicellular and have lateral 
germ-pores. The teleutospores are also unicellular, and form lentil-shaped 
patches composed of five or more layers of spores ; the spores have a 
somewhat thickened apex, but no distinct germ-pore. 

U. chenopodii (Duby). On Chenopodium and Sckoberia. 

U. terebinthi (D. C.). On Pistacia and Rhus (U.S. America). 

U. brevipes (B. et R.). On Rhus Toxicodendron in America. 

U. ambiguus (D. C'.). On Allium Scorodoprasum. 

U. acutatus (Fuck.). On Allium. 

U. veratri. (D. C.). On Veratrum. 

U. alchemillae (Pers.) (Britain). This is a species which 
in habit resembles a Phragmidium, and is sometimes regarded 
as a representative of a separate genus — Trachyspora (Fuck.). 
It forms patches of reddish-yellow uredospores or brown teleuto- 
spores on the lower surface of leaves of Alcliemilla vulgaris. 
Aecidia are unknown. 

(4) Pycnidia, aecidia, and teleutospores on the same host-plant ; 
uredospores unknown. 

Uromyces excavatus (I). C.) Magn. On Euphorbia Ger- 
arcliana, E. verrucosa, etc. 

U. Behenis (D. C.). On Silene. (Britain.) 

U. lapponicus Lagerh. On Astragalus in Norway and the Alps ; aecidia 
only in the latter locality. 

1 Benchte d. deutsch. botan. Ges., 1896, p. 130. 

Y 


338 


UREDINEAE. 


U. minor Schroet. On Trifolium montanum (U.S. America). 

U. hedysari-obscuri (D. C.). On Hedysarum in Europe and America. 

U. scrophulariae (D. C.). On Scropkxdaria and Verbascwm (Britain). 

U. erythronii (D. C'.). On Lilium, Muscari, Scilla, Allium, Fritillaria. 
{U.S. America). 

(5) Teleutospores alone known ; after death of the hod they 
undergo a reding -period, then germinate : 

U. solidaginis (Somm.). On Soli da go virgaurea. 

U. phyteumatum (D. C.). On Phyteuma , accompanied by elongation of 
the leaf-stalk. 

U. scillarum (Grev.). On Scilla and Muscari. (Britain.) 

U. ornithogali Lev. On Omithogalum and Gagea. (Britain.) 

U. colchici Ma.ssee. On Colchicum spectabilis at Kew. 1 

(G) Televtospores alone known ; germinating at once on the 
living hod : 

U. pallidus Niessl. On Cytisus. 

(7) Only teleutospores and pycnixlia known; present on the same 
host : 

Uromyces Tepperianus Sacc. 2 This causes on twigs and 
branches of Acacia a deformation consisting in an all-round 
swelling followed by rupture of the periderm and the develop- 
ment of brown teleutospore patches on the exposed wood. Topper 
found in South Australia shrubs of Acacia salicinia and A. 
myrtifolia attacked and killed ; the former, near Adelaide, being 
almost exterminated. He also found it prevalent on Acacia 
spincsccns, A. hakioides, and A. myrtifolia in another part of 
Australia (Murray Bridge). 

The same fungus was found by Warburg on Albizzia manta no 
in Java, likewise by Sol ms- Lau bach and Stahl (Fig. 181). 

Magnus 3 found that Warburg’s specimens showed the rupture 
of the rind only on one side, those of Stahl, however, agreed 
with the Australian specimens. On investigation of the galls, 
Magnus found a multiseptate and intercellular mycelium with 
numerous and somewhat branched haustoria. The formation 

1 Grevillea xxi., 1892, p. (>. 

2 Ludwig, “Fine none Rostknuiklieit nustrulischer Akazien," Centru/b/att f. 
link/er n. Parasite.nkumle, 1890, p. 83: further: Jfcdtrigia, 1889, anil For*/- 
lich-naturwiss. Zeitschrifl, 1S94. 

'Magnus, Ber. il. deulsch. Itolan. Gene //. , 1892, p. 195; Hennings, Fungi 
Warburgiani, Iledwigia, 1893. 


UROMYCES. 


339 


of pycnidia precedes that of teleutospores. The latter have 
a flattened concave base and rounded apex ; their episporium 
is marked with delicate ribs running from apex to base. 



Fig. 181 . — Uromyces Tepperianus on twigs of Albizzia montanci brought by 
Prof. Stahl from Java. (v. Tubeuf phot.) 

Puccinia. 

Teleutospores two-celled, and each abjointed from its own 
sporophore from large distinct sori. Each cell has as a rule 
only one germ-pore. Uredospores, teleutospores, and pycnidia 
(spermogonia) are not known in all the species. 

( 1 ) Pycnidia, aecidia, uredospores, and teleutospores develop on the 



340 


UREDINEAE. 


living host. The latter, however, germinate only on death of the 
host and after a resting-period (Eu-puccinia, Schroeter). 

(a) Auteupuccinia : all forms of spore are present on the same 
host-plant. 

Puccinia helianthi. Schwein. Sunflower-rust. This danger- 
ous enemy of Helianthus was first observed in South Carolina 
and Pennsylvania, U.S. America. In Europe it appeared first 
to a serious extent in Russia, where the sunflower is cultivated 
on a large scale ; now it has a very general distribution. In 
America it attacks both sunflower (II. annuns) and Jerusalem 
artichoke (II. tuberosus), but its presence on the latter is as 
yet doubtful in Europe. The mycelium appears first in the 
lower parts of the plant and thence extends upwards ; its 
presence is indicated by large brown leaf-spots, on which the 
uredo-patches arise about the end of June. The teleutospores 
make their appearance in autumn ; the aecidia and pycnidia in 
spring ( A<e . helianthi Wor.). Combative measures consist in 
burning, or otherwise destroying, all sunflower debris in autumn. 

P. cirsii Schroet. On Cardans lanceolata. (Britain.) 

P. prenanthis (Pers.). On Prcnanthes, Lactuca, and Mxdge- 
dium. (Britain and U.S. America.) 

P. lampsanae (Schultz). On Lamjtsana. (Britain.) 

P. montana Fuck. On Centaurea. 

P. violae (Sebum.). (Britain and U.S. America.) The Violet- 
rust. This parasite appears on both wild and cultivated species 
of Viola, and frequently causes much damage. Malformation 
and stunting of the host may accompany the formation of 
aecidia. Fentzling investigated the swollen outgrowths produced 
on the lower surface of the violet leaves, and found an increase 
in all forms of the leaf-parenchyma ; the spongy parenchyma 
included more cells, while both spongy and palisade parenchyma 
consisted of rounder cells more closely packed together than in 
the normal. 

P. aegra (hove. On Viola eornuta, etc., and somewhat 
different from the last species. (Britain.) 

P. mirabilissima Peck. On Berberis ripens in America. 

P. silenes Schroet. On Silene and Lychnis, (Britain.) 

P. pimpinellae (Strauss). On Pimpiniila, Chacrophyllum, 
Anth risers, Myrrhis, Athamavtha, Ostcrieum, Angelica, Hcraelcum, 
Eryngium, etc. (Britain and U.S. America.) 


PUCCINIA. 


341 


P. saniculae Grev. On Sanicula europaea. (Britain and 

U.S. America.) 

P. soldanellae (D.C.). (Britain.) On various species of 

SoldaneUci. This disease is often very common in the mountains, 
and is conspicuous because it attacks only leaves here and there 
on a plant. The leaves are yellowish with petioles distinctly 
elongated ; their laminae, which bear aecidia on the lower side, 
are smaller and somewhat cup-shaped. Diseased plants do not 
seem to bloom. 

P. menthae (Pers.). (Britain and U.S. America.) This is 

a most destructive rust to all kinds of cultivated mint. It 

attacks species of many genera of Labiatae. 

P. calthae Link and P. Zopfii Wint. On Calthn palustris 
in Europe and North America. 

P. epilobii-tetragoni (D.C.) (P. pulverulenta Grev.). On 
Epilobium. (Britain and U.S. America.) 

P. Peckiana Howe [P. interstitialis (Schlecht.)]. This species 
occurs on several species of liubus in America, and causes con- 
siderable damage in blackberry culture . 1 

P. gentianae (Strauss). On Gentian. (Britain and U.S. America.) 

P. galii (Pers.). On Galium and Asperula (Woodruff). The teleutospores 
hibernate on the dead stems. (Britain and U.S. America.) 

P. convolvuli (Pers.). On Convolvulus. (Britain and U.S. America.) 

P. primulae (D. C.). On species of Primula. (Britain.) 

P. obtusa Schroet. On Salvia verticillata. 

P. thesii (Desv.). On Thesium. (Britain and U.S. America.) 

P. albescens (Grev.). On Adoxa Moschatellina. (Britain.) 

P. aristolochiae (B. C.). On Aristolochia. 

P. asparagi (D. C.). (Britain and U.S. America.) Asparagus-rust. The 
teleutospores hibernate in dry remains of the plants, which should therefore 
be burnt in autumn. 

P. porri (Sow.) Onion-rust. On both wild and cultivated Allium. 
Sometimes very destructive to chives (A. schoenoprasum). (Britain.) 

( b ) Hetereupuccinia. Uredospores and teleutospores developed 
on a host other than that of the pycnidia and aecidia. 

Puccinia graminis Pers. (Britain and U.S. America). Black- 
rust or summer-rust . 2 Uredospores and teleutospores occur on 
various species of Gramineae, the pycnidia and aecidia on 
species of Berberis or Mahonia. 

' Clinton in Report of Agricultural Station of University of Illinois, 1893. 

2 A valuable monograph on the rusts of cereals has been published by 
Eriksson and Henning (Die Getreiderostc, Stockholm, 1896). 


342 


UREDINEAE. 


The two-celled teleutospores arise from cushions or sori 
which form black lines on the haulms and leaves of grasses ; 
they hibernate on the decayed remains and germinate in spring. 

Each cell of a germinating teleutospore 
gives off a four-celled basidium (promy- 
celium), with four short sterigmata from 
each of which a basidiospore (sporidium) 
is abjointed (Fig. 182). The sporidia are 
carried off the grass-host and germinate at 
once if they alight on leaves or flowers of 
Berberi# or Malionia (Fig. 183). Germ- 
tubes are formed which penetrate the outer 
walls of the host into the epidermal cells. 
The mycelium which results is a branched 
septate one, and spreads through the inter- 
cellular spaces of the leaf. About eight 
days after infection, little yellow spots make 
their appearance on the upper surface of 
the leaf. Embedded in the spots will be 
found the pycnidia (spermogonia), spherical 
flask-shaped enclosures developed on a web 
of hyphae, and with their inner walls clad 
with short rod-shaped conidiophores (sterig- 
mata), each of which gives off a tiny coni- 
dium (spermatium) (Fig. 184). A tuft of 
periphyses arising from the upper part of 
the pycnidium wall carries the conidia out 
of the pycnidia in drops of a honey-like 
fluid emitting a characteristic odour. In 
regard to the function of these conidia 
nothing definite is known. 

The next stage begins with the appear- 
ance of yellow spots on the lower epidermis 
of leaves. These indicate the presence of 
a mycelium from which the aecidia take 
their origin. The aecidia are at first en- 
closed in a one-layered peridium under 
the leaf-epidermis, till by their increasing size they rupture both 
coverings, and project above the surface as cups containing 
spores (Fig. 184). The aecidiospores originate in a layer of 


FlO. 182. — Pnccinia pram- 
ini*. Germinating teleuto- 
spore. The promycelium 
has formed three sterigmata, 
from the ends of which 
sporidia are in process of 
abjunction. (After Tuhisnc.) 


PUCCINIA. 


343 


hyphae forming the bottom of the aecidium-cup. These hyphae 
give rise to numerous short sporophores, from each of which 
a single long chain of spores is abjointed in basipetal succession, 
the spores being at first separated by temporary intermediate 
cells. The sporophores round the margin of each aecidium do 
not, however, give off spores ; they also produce chains of 
cells basipetally, but these grow larger and, without the inter- 
vention of intermediate cells, remain sterile and become joined 



Fig. 183. — Puccinia graminis ( Aecidium berberidis ) oil Berberis communis. The 
lowest leaf and two others are seen on the upper surface, and show red spots with 
light margins, in which the pycnidia are embedded. The other leaves show the 
under surface with patches of aecidia. (v. Tubeuf del.) 


to their neighbours to form the peridium. Diseased portions 
of leaves become considerably thickened. The cells of the 
single layer of palisade parenchyma are abnormally elongated, 
and the intercellular spaces of the spongy parenchyma, instead 
of being large, are small and filled with mycelium. The aecidio- 
spores escape in July to germinate on Gramineae. The germ- 
tube enters the host by the stomata only, and develops into 
an intercellular mycelium ; this in about eight days produces 
uredospores from cushions or sori which form lines, and break 


3 44 


L'REDINKAE. 


through the epidermis. The yellow uredospores are abjointed 
n ly from long sporophores ; they are unicellular and ovoid with 
a thin granular coat beset with germ-pores (Fig. 184;. The uredo- 
spores are easily conveyed to other grass-plants and germinate at 
once, their gerjn- tubes entering by a stoma and developing hito 
mycelium, which can produce a new crop of uredospores in a 



uomS C «t°rTicture U a!ld l thrckneM n of ) ^he n fe«/ > '! t 1 “ ^ A * ' 

abnormally thickened ; A to o. upper *i[rfkc?of the w"’ h ° '"TV."" “ *° " is 

^ridCn exposed 

*. 

at iu apex,^t S lS* , |Sed'i.BpmiM re hi"v^ , 0 fo,*[. 'gernvMres^it* tl^t ^ 0 h "" 

(After lie Bare, from Sach a ItArbueh.) ^ * heir *> u,l,or - * m. 


few days. The uredospores are summer-spores, and spread the 
fungus during the vegetative period of the host-plant ; they may 
however, hibernate. The teleutospores are more suited for' 
hibernation; they are produced in autumn from dark brown 
linear son, distinguished from these of the uredospores by their 
darker colour and greater length. The teleutospores are two-celled 
and obovoid with smooth thick walls (Fig. 184); they are like 


rtJCCINIA. 


345 


the uredospores, developed from long sporophores, and are in 
this way distinguished from those of Pucc. rubigo-vera, which 
are very short. The teleutospores germinate in spring after 
hibernation, each cell giving off a single germ-tube. 

Both uredospores and teleutospores are injurious to our 
cereals, — wheat, oats, and rye. They may also be found on 
the following species of grasses : Anthoxanthum, Alopecurus 
Phleum, Agrostis, Aim, Avena, Briza, Arrhenatherum, Poa, 
Dactylis, Festuca, Bromus, Triticum, Secede, Elymus, Hordeum, 
Lolium, Agropyrum, Andropogon, Bryzopyrum, etc. 

The disease may ruin a whole harvest of grain, and render 
the straw disagreeable, if not dangerous, for stable use (see 
also p. 84). Removal of barberry bushes is said to reduce the 
rust, although many believe that the barberry is not necessary 
for the existence of the fungus. 1 Plowright, for example, found 
that sporidia from teleutospores infected wheat-seedlings directly, 
without intervention of the aecidiospore stage. It is also possible 
that the mycelium hibernates like that of Pucc. rubigo-vera, in 
some wild grass, to grow again and produce uredospores in spring. 

No very effective measures against this fungus are known. 
Early sowing has been suggested; and certain varieties of grain, 
known to be less liable to attack than others, might be used. 

Eriksson and Henning, 2 from the results of their infection- 
experiments, have provisionally distinguished the following 
varieties of P. graminis: 

A. Definite — (a) distinct varieties : 

1. Var. secalis on Secede ccreale, Hordeum vulgare, Triticum 

repens, and Elymus arenarius. 

2. Var. avenae on Avena saliva, Milium effusum, Alopecurus 

pratensis, Dactylis glomerata (and Arena eledior). 

3. Var. airae on Air a cacspitosa. 

(ft) somewhat uncertain varieties : 

4. Var. agrostis on Agrostis canina, and A. stolonifera. 

5. Var. poae on Poa compressor (and P. pratensis). 

B. Not sharply defined : 

6. Var. tritici on Triticum vulgare. 

1 An interesting discussion of this subject is given by Wor. G. Smith (Diseases 
of Crops, Chap. xxv.). (Edit.) 

-Eriksson and Henning, “ Untersuchungen iib. d. Getreideroste, ” Zeitscli. 
f Pflanzenkrankheiten, 18514. 


346 


UREDINEAE. 


Puccinia coronata Corda. (Britain and U.S. America.) 
Eriksson, from his own experiments and those of Klebahn, 
distinguishes the following specialized varieties : 

Ser. I. Aecidia on Rhamnus cathartica, Rli. elaeoides, Rli. 
grandifolia, Rh. alnifolia ( Puccinia coronifera Kiel).). 

1. Yar. avenae on Avena scitiva. 

2. Yar. alopecuri on Alopccurus prcitensis. 

3. Yar. festucae on Festuca elatior (and F. rubra). 

4. Var. lolii on Lolium perenne. 

In addition to these, Klebahn found a form on Avena elatior , and one 
on Holms lanatus , in regard to whose specialization nothing is known. 

Ser. II. Aecidia on Rhamnus Franqula ( Puccinia coronata I., 
Kleb.). 

5. Yar. calamagrostis on Calamagrostis arundinacea (and 

C. lanceolata). 

In addition : forms on Dactylia glomerata, Festuca sylvatica (? Puce, 
gibberosa Lagerh.), Agrostis vulgaris, Holms lanatus (? H. mollis), and 
P/talaris arundinacea. 

Ser. III. Aecidia on Rhamnus dahurica {Pace, coronata var. 
himalensis, Barcl.). 

Indian forms on Brachypodium sylvaticum, ( Piptatherum holciforme. and 
Festuca gigantea,) of which nothing more is known. 

Ser. IY. Aecidia unknown, probably do not exist. 

6. Yar. melicae on Mclica nutans. 

Amongst our cereal crops the oat alone is attacked by this 
species, and much damage may result. 

The uredo-patches have no paraphyses like the preceding 
species, and they form reddish -yellow spots and stripes; the 
teleutospore-patches are black. The upper cell of the teleuto- 
spores is surrounded by a crown of six or seven blunt teeth. 

The presence of aecidia on Rhamnus is accompanied by 
thickening and twisting of young shoots, and blister-like de- 
formation of leaves, calyces, and ovaries. Wakker 1 thus 
summarizes his investigations on the anatomical changes induced 
by the fungus on Rhamnus Frangula : “It causes the cells 
of every part to become abnormally enlarged, at the same time 
giving rise to an orange coloration of the cell -sap and an 
accumulation of starch ; there is no longer any formation ot 
interfascicular cambium, and there is a partial or complete 
1 Wakker, Pringsheim's Jahrbuch, 1892. 


PUCCINIA. 


347 


suppression of secondary vasa, mucilage canals, and calcium 

oxalate.” 

The deformation induced by P. coronata on Rhcimnus cathartica 
was investigated by Fentzling. 1 The changes were relatively 
slight : the parenchymatous cells of the rind were enlarged 
and separated by large intercellular spaces ; so also the paren- 
chyma of the bast ; vessels were more numerous in the wood 
affected : the epidermal cells in some parts of the leaf were 
broadened and those of the mesophyll enlarged, abnormally 
shaped, and with large intercellular spaces ; in diseased leaf- 
stalks the epidermal cells are thinner- walled and broader, while 
all parenchymatous cells become enlarged, thinner-walled, and 
with many intercellular spaces ; the fibro- vascular bundles are 
enlarged, chiefly from an increase of the wood-parenchyma ; this 
tissue, in normal petioles, occurs as single rows of cells running 
radially between the vessels, whereas, in diseased places, three 
parallel layers of cells may separate neighbouring vessels. 

P. dispersa Eriks, et Henn. Brown-rust. (Britain.) The follow- 
ing specialized varieties of this species have been distinguished : 

Ser. T. Aecidium on Anchusa arvensis and A. officinalis ( Aec . 
anchusae). 

1. Yar. secalis on Secede cerecdc. 2 

Ser. II. Aecidium unknown. (Whether distinct varieties, 
somewhat uncertain.) 

2. Yar. tritici on Triticum vulgare. 

3. Yar. bromi on Bromus arvensis (and Be. brizaeformis). 

4. Yar. agropyri on Triticum repens. 

P. rubigo-vera (D.C.) (P. straminis Fuck., P. striaeformis West.). 
(Britain and U.S. America.) This, in its uredo- and teleuto- 
spore stages, frequents various grasses, while the aecidia occur on 
Boragineae. A variety on species of Hordeum has been designated 
P. simplex. The teleutospore-patches are enveloped in numerous 
brown paraphyses ; the teleutospores have very short stalks. 

The anatomical changes produced in leaves beset with aecidia 
have been stated by Wakker as follows : The swelling of the 
leaf-petioles is due to enlargement of their cells ; the large 
intercellular spaces of the spongy parenchyma are no longer 

1 Fentzling, Inaugural Dissertation. Freiburg, 1892. 

2 Found along with the Aecidium at Montrose (Scotland) by Prof. J. W. H. 
Trail. (Edit.) 


348 


UREDINEAE. 


present ; the palisade layer is doubled, and rupture of the 
epidermis takes place ; chlorophyll-formation is suppressed, the 
cell-sap becomes yellow, and starch tends to accumulate. 

P. (lispersa may cause serious damage to wheat and rye ; P. 
rvhigo-vera , also on barley and oats. The spore-patches are 
found on stalks and leaf-sheaths more than on the lamina. The 
mycelium may hibernate in grasses, so that the fungus is not 
dependent on the aecidial stage; for this reason the disease is 
not easily combated. 

P. glumarum Eriks, et Henn. Golden-rust. This species, 
hitherto generally included under P. rubigo-vem (D. C.) has been 
separated by Eriksson and Henning. 1 Experimental infection 
on Boragineae gave negative results. 

Eriksson distinguishes the following specialized varieties of 
this species : 

A. Definite (and undoubtedly distinct). 

1. Var. tritici on Triticum vulgare. 

2. Var. horrid on Horrimm vulgare (somewhat uncertain). 

3. Var. elymi on Ply mas arcnarius. 

4. Var. cigropyri on Triticum repens. 

B. Not sharply defined : 

5. Var. secalis on Secalc cereale. 

The uredospore-sori are lemon-yellow in colour, and form 
lines on the leaf-blade which may run together and reach a 
length of 10 mm. The teleutospore-sori form long, fine, brown 
or black lines: the sori are divided into numerous chambers, 
each enclosed in a circle of curved brown parapbyses. The 
spores germinate in the autumn of the same year. The pro- 
mycelium is yellow till the spores are abjointed : in this way 
it is distinguished from P. dispersa. 

P. poarum Niels. (Britain). Credo- and teleutospores on 
Pan. According to Nielson, the aecidia occur on Tussilago, 
Petasites, and Adr nostyles. Fentzling {lor. cit.) has described 
certain anatomical changes which accompany deformations due 
to the aecidia. 

P. phlei-pratensis Eriks, et Henn. This has a hibernating mycelium 
which produces uredospores continuously on /‘/drain and probably also 
on Festuca. Aecidia have not as yet been observed. 


1 Eriksson and Henning (foe. cit.). 


PUCCINIA. 


349 


P. agrostidis Plowr. 1 Teleutospores on Agrostis vulgaris ; aecidium = 
Aec. aquilegiae Pers. (Britain and U.S. America). 

P. festucae Plowr. 1 Uredo- and teleutospores on Festuca ovina and F. 
duriuscula ; aecidium =Aec. periclymeni Schum. (Britain). 

P. phragmitis (Schum.). Uredo- and teleutospores on Phragmites. 
Aecidium = Aec. rubellum on Rume.i crispus and other species of Rumex , 
also on Rheum. (Britain and U.S. America.) 

P. Trailii Plowr. Uredo- and teleutospores on Phragmites communis. 
Aecidium on Rumex Acetosa. (Britain.) 

P. Magnusiana Korn. Uredo- and teleutospores on Phragmites communis. 
Aecidium on Ranunculus repens. (Britain.) 2 

P. moliniae Tul. Uredo- and teleutospores on Molinia coerulea . Aecidium 
(according to Rostrup's out-of-door experiments), on Orchis repens, 0. mascula ; 
probably also on other Orchideae. (Britain.) 

P. nemoralis Juel. Uredo- and teleutospores on Molinia coerulea ; 
aecidium (Aec. melampyri Kze. et Selim.) on Melampyrum pratense. 

P. australis Korn. Uredo- and teleutospores on Molinia in Tyrol ; 
aecidium (Aec. erectum, according to Pazschke) on Sedum reflexe, S. acre, etc. 

P, perplexans Plowr. Uredo- and teleutospores on Alopecurus pratensis ; 
aecidium on Ranunculus acris. (Britain.) 

P. persistens Plowr. On Triticum repens. Aecidium = Aec. thalictri 
(Britain). 

P. sesleriae Reich. On Sesleria coerulea. Aecidium on Rhamnus 
saxatilis. 

P. Winteriana Magn. 3 (P. sessilis, Schn.). Uredo- and teleutospores on 
Phalaris arundinacea. Aecidium on Allium ursinum (Aec. alliatum Rbh.). 

P. sessilis Schn. (including P. digraphidis Soppitt and P. paridis Plowr.) 
(Britain.) Uredo- and teleutospores on Phalaris arundinacea. Aecidium, 
according to Soppitt, 4 on Convallaria majalis, also on Majanthemum, Paris, 
Polygonatum, Lilium canadense and Streptopus Smilacina. Klebahn’s experi- 
ments confirm the relationship of the aecidium on Majanthemum, Convallaria, 
Polygonatum, and Paris. 

P. phalaridis Plowr. On Phalaris arundinacea. Aecidium (Aec. ari) on 
Arum italicum and A. macidatum. (Britain.) 

P. agropyri Ell. et. Ev. On Agropyrum. Aecidium = Aec. clematidis 
D. C. on Clematis Vitalba and C. recta, etc., in Europe and America. 

P. caricis (Schum.) (Britain and U.S. America). Uredospores 
and teleutospores on species of Carex. Aecidia, according to 
Magnus, on Urtica (Fig. 185). The same author also believes 
that the uredo-stage can hibernate. 

1 Plowright, Grevillea, xxi., 1893, p. 109. 

2 Klebahn (Zeitsch. f. Pjlanzenkrankheiten, 1892) confirms Plowright’s observa- 
tions on this. 

3 Magnus, Hedivigia, 1894. 

4 Soppitt, Journal of Botany, 1890. 


350 


UREDINEAE. 


Stems, leaf-stalks, and leaf-nervature often undergo one-sided 
thickening and curvature as a result of formation of aecidia. 
Wakker thus summarizes his observations on the anatomical 
changes in these malformed parts of Urtica : there is an en- 
largement of cells and an increase in the number of large inter- 
cellular spaces ; no formation of collenchyma, interfascicular 
cambium, and chlorophyll ; a diminished formation of calcium 
oxalate ; an orange coloration of the cell-sap ; and a distension 
or rupture of the epidermis. 



Fio. 185 . — Puccinia caric is on Stinging Settle. The uecidiul cushions have caused 
swelling and distortion of stems and leaf-stalks, also swollen outgrowths on the 
leaves, (v. Tubcuf phot.) 


Klebahn and Magnus believe that there is a Puccinia on 
Career, acuta and C. Goodenoughii related to an Accidium on 
Riles Grossularia, It. rubrum, and R. ann um ; also a Puccinia 
on Carex riparia with an Accidium on Ribcs nigrum. On this 
account Klebahn 1 distinguishes Pure, caricis l., ll., and ill., 
agreeing respectively with P. Pringshcimiana Kleb., P. caricis 
(Sebum.), and P. Magnusii Kleb. 

P. Schoeleriana l’lowr. et Magn. 2 (Britain). 1 redo- and 
teleutospores on Carex armaria : aecidia on Scnrcio Jacobaea. 

•Klebahn, Zeituchri/l f. PjianzenLraukhtittn , IS'VJ, 1894, and 1S95. 

2 Hedicigia, 1880. 


PUCCINIA. 


351 


P. sylvatica Schroet. (Britain). Uredo- and teleutospores on 
Carte ; aecidia on some Compositae. Schroeter 1 regards an 
Aecidium on Taraxacum officinale and Senccio nemorensis as 
related to the teleutospores on Carcx brizoides and C. praecox. 
Klebahn 2 reared aecidia on Taraxacum after infection with 
teleutospores from Car ex arenaria ; E. Fischer obtained aecidia 
only on Taraxacum officinale. Dietel 3 regards Aecidium 
Bardanac on Arctium Lappa as related to this species. 

Attacked leaves of Taraxacum are frequently much deformed, 
stunted, and twisted. Those of T. officinale have orange-red 
warts on the lower surface, and there Fentzling ( loc . cit.) found 
both spongy and palisade parenchyma increased and more or 
less deformed, the cells being elongated and enclosed in 
hyphae. 

P. leucanthemi Pass. According to E. Fischer, the uredo- and teleuto- 
spores are found on Care.v montana ; the aecidia (Aec. leucanthemi) on 
Chrysanthemum Leucanthernum. 

P. tenuistipes Rostr. Uredo- and teleutospores on Carer muricata ; 
aecidia on Centaurea. 

P. arenariicola Plowr. et Magn. On Carer arenaria ; aecidia = Aec. cent- 
aureae on C. nigra. (Britain.) 

Ed. Fischer found that the species of Puccinia on Carer montana (one 
with its aecidia on Centaurea Scabiosa, the other on Centaurea montana), 
were specifically different. 

P. limosae Magn. Uredo- and teleutospores on Carer limosa ; aecidia 
on Lysimachia. thyrsifolia and L. vulgaris d 

P extensicola Plow. (Britain.) Uredo- and teleutospores on Carer 
ertensa ; aecidia on Aster Tripolium. 

P. dioicae Magn. (Britain and U.S. America). Uredo- and teleutospores 
on Care.v dioica and C. Davalliana ; aecidia on Cirsium (according to Rostra p 
and Schroeter). 

P. firma Dietel. Teleutospores on Carer fir ma; aecidia on Bellidiastrum. 

P. vulpinae Schroet. Uredo- and teleutospores on Carer vulpina ; 
aecidia on Chrysanthemum TanaceturnX 

P. paludosa Plowr. (Britain). Uredo- and teleutospores on Carer vulgaris, 
etc. Plowright gives Aecidium pedicidaris as the aecidial form. The 
attacked plants of Pedicularis are often considerably deformed. 

P. uliginosa Juel. 6 Uredo- and teleutospores on Carer vulgaris-, 

1 Pilze Schlesiens. 

2 Klebahn, Zeitschrift f. PJlanzenkrankheiten, u., 1892. 

3 Dietel, Oesterreich. botan. Zeitung, 1889. 

4 Magnus, Tagbl. d. Naturforsch. Vereins in Miinchen, 1877. 

5 Schroeter, Pilze Schlesiens. 

B Juel, J fy colog. Beit. Vetenscaps-Akad. Forhandl, 1894. 


352 


UREDINEAE. 


aecidia (Aec. parnasnae Scldecht.) on Parnassia palustris. Spermogonial 
pycnidia are unknown. 

P. scirpi D. C. (Britain). Uredo- and teleutospores on Scirpus ; aecidia, 
according to Chodat, = A ec. nymphaeoules on Nymphaea, Nupkar, and JAm- 
nanthemum nymphaeoides. 



Flo. 180. — Pucania guavcoUn* on Cirgivni arvcnge. The plants ftro abnormally 
elongated ; the leaves have remained smaller and simpler, and are thickly beset 
on the lower side with patches of chocolate-brown uredospores. (v. Tubcul phot.) 

P. eriophori Thiim. Uredo- and teleutospores on Knophonnn lattfoliuin 
in Siberia and Denmark ; Rostrup gives as the aecidial form Aec. cineranac 
Rostr. 

P. obscura Schroet. Uredo- and teleutospores on Luzulo ; aecidia on 
Ilellis perennU (Plowright). (Britain and U.S. America.) 

P. septentrionalis Juel. Uredo- and teleutospores on Polygonum vin- 
parum ; aecidia (.ler. Sommer feltii) on Thahctrum alpmuin in Scandinavia, 


PUCCINIA. 


353 


Iceland, Greenland, and Switzerland. Juel states that this is the only 
heteroecious Puccinia whose uredo- and teleutospores inhabit a dicotyle- 
donous plant. 

(2) Aecidia are absent ; pycnidia, uredospores, and teleutospores 
developed on the same plant. ( Bracliypuccinia , Schroet.) : 

Puccinia suaveolens (Pers.) (Britain and U.S. America). 
One form on Cirsium arvense, and a second on Centaurea Cyanus. 
Pycnidia and uredospores appear first, then teleutospores develop 
amongst the later-formed uredospores. 

The shoots and leaves of attacked plants are permeated with 
mycelium and rendered conspicuous by their elongated shape, 
lighter colour, and smaller, less lobed, softer leaves (Fig. 186). 
Diseased plants bear no flowers. Wakker on investigating the 
diseased stems found : non-development of those sclerenchyma- 
sheaths of the primary tissues situated towards the interior of 
the stem, whereas those towards the outer side show secondary 
thickening ; irregularities occur in the interfascicular cambium, 
so that the phloem becomes abnormally developed and propor- 
tionately more extensive than the wood, it may also be divided 
by a band of sclerenchyma. 

P. hieracii (Schum.) (Britain and U.S. America). On numerous Com- 
positae, e.g. Cartina , Cirsium, Carduus, Centaurea , Leontodon, Scorzonera , 
Crepis, Hieracium, Cichorium , etc. 

Plowright distinguishes two allied species on Compositae, viz. P. 
centaureae, Mart, on Centaurea nigra, and P. taraxaci Plowr. 

P. bullata (Pers.) (Britain and U.S. America). On Umbelliferae, e.g. 
Apium, Petroselinum , ZEtliusa, Selinum, Conium, Anethum , etc. On culti- 
vated species {e.g. Parsley, Dill, Celery, etc.) it may prove troublesome. 1 

P. oreoselini (Strauss). On Peucedanum and Seseli. (U.S. America.) 

P. helvetica Schroet. On Asperula taurina. 

(3) Uredospores and teleutospores alone known. The related 
pycnidia and aecidia have either not as yet been traced, or do 
not exist. ( Hcmipuccinia , Schroet.): 

Puccinia sorghi Sclnvein. ( Pucc . maydis Ber.). This rust of 
Sorghum and Zea Mais occurs in America, Italy, Germany, etc. 
The leaves become more or less beset with little pustules, in 
which the sori of uredospores or teleutospores are contained 
(Fig. 187-189). 

P. purpurea Cke. On Sorghum vulgare in India, and Zea in Africa. 

1 Description and figures in A r . J. Agric. Exper. Station Report, 1891. 

Z 


354 


UREDINEAE. 


P. elymi West. ( Rostrupia elymi Lagerh.). On Elymus arenarius and 
E. mollis. 

P. Baryi (Berk, et Br.). On Brachypodium in Europe and Britain, 
Bambusa Thouarsii in India, Andropogon, etc., in America. 

P. longissima Schroet. On Koeleria cristata in Germany ; K. Berythria 
in Egypt. 



Fig. 187 . — Puceinio. norghi 
(Pv.cc. maydis). Portion of 
.Maize-leaf showing spore- 
patches. (v. Tubeuf. del.) 



Fig. 189. — Puccini a norghi. Three teleutosporcs and two 
uredospores. One of the latter exhibits the tiny point-like 
projections of the membrane, (v. Tubeuf del.) 



Fig. m.—Puccinia norghi. Section of leaf of Zta .Voin filled with mycelium. 
I he epidermis is ruptured by a spore-sums. At one end there arc still the remains 
of a uredospore-soms and a few uredospores. (v. Tubeuf. del.) 


P. paliformis Fuck. On hoeleria crista fa. (Britain.) 

P. anthoxanthi buck. On . I ntho.cant hum odoratum. (Britain.) 

P. gibberosa T/agerh. On Frstuca si/lvatica. 

P. angustata I’eck. On Scirpus and Enophorum. (U.S. America.) 
P. junci (Strauss). On J uncus. (U.S. America.) 

P. oblongata (Lk.). On Lmula. (Britain.) 


PUCCINIA. 


355 


P microsora Korn. On Carex vesicariu. 

P. caricicola Fuck. On Carex supina. 

P. allii (D. C'.)> Onion-rust. (U.S. America.) 

P. iridis (D. C.). On Iris. (Britain.) 

P. veratri Niessl. On Veratrum album and V. viride. (U.S. America.) 

Puccinia pruni Pers. Plum or Prune Eust. [This is a 
common species in both Europe and the United States ; it 
attacks almost every kind of cultivated drupaceous fruit, includ- 
ing prune, plum, peach, nectarine, apricot, cherry, and almond. 
The uredospores are brown, the teleutospores darker, and both 
are as a rule found only on the under surface of the leaf 
(Fig. 82). The leaves first show yellowish or reddish spots 
which rapidly enlarge and darken in colour till rupture of the 
epidermis takes place, and they rapidly dry up. The fruit is 
thus altogether lost or much injured, while ripening of the wood 
is more or less interfered with. 

The remedies suggested are : sprayings with modified eau 
celeste, or ammoniacal copper carbonate (see p. 69)]. 1 (Edit.) 

P. cerasi (Bereng.) Cherry-rust on Primus Cerasus, P. Anxygdalus , 
and P. Persica. 

P. oenotherae Yize. On American species of Oenothera. 

P. giliae. Hark. On Phlox and Cilia. (U.S. America.) 

P. tanaceti D. C. On Tanacetum vulgare. (Britain and U.S. America.) 

P. sonchi Bob. et Desm. On Sonchus. (Britain.) 

P. endiviae Pass. On CichoriJ Endivia in Italy. 

P. carthami Corda. On Carthamus tinctoria. 

P. balsamitae (Strauss). On Tanacetum Balsamita. 

P. picridis Haszl. On Picris in Hungary. 

P. bistortae (Strauss) (Britain and U.S. America). On Polygonum 
Bistorta and P. viviparum. The teleutospores have no papilla on their 
germ-pores. Soppitt ( Grevillea , 1894) claims relationship between this 
species and an Aecidium on Conopodium denudatum ( Aec . bunii (!)). 

P. mammillata Schroet. (U.S. America). On Polygonum Bistorta. The 
upper cell of the teleutospore has an apical thickening. 

P acetosae (Schum.). On Rumex Acetosa, R. arifolia, and R. Acetosella. 
Ludwig says it hibernates in the uredo-form. 

P. polygoni Pers. (Britain and U.S. America). On Polygoneae. 

P. rumicis-scutati (I). C.). On Polygoneae. 

P. oxyriae Fuck. (Britain and U.S. America). On Oxyria. 

P. castagnei Thiim. On Apium graveolens in France. 

P. cicutae Lascli. On Cicuta virosa. 


/cm. 


1 Pierce (Journal of Mycology , vii., p. 354) gives an account of this disease as 
found in California, and describes application and results of various remedies. 


356 


UREDINEAE. 


P. stachydis D. C. On Stachys recta. 

P. argentata (Schultz). On Impatiens. (Britain and U.S. America.) 

P. Berkeleyi Pass. On Vinca. (Plowright distinguishes also P. vincae.) 
(Britain.) 

(4) Uredospores absent or only rudimentary. The other spore- 
forms — pycnidia, aeeidia, and teleutospores — develop on the same 
host-plant. ( Pucciniopsis , Schroet.) : 

Puccinia tragopogonis (Pers.) (Britain). On Tragopogon, 
Scorzonera, Podospermum, and Galasia. The leaves of diseased 
plants are conspicuous in spring from their slenderness and 
pale colour. 

P. senecionis Lib. 1 (Britain). The mycelium inhabits species 
of Senecio ; it probably arises from aecidiospores, and produces 
both aeeidia and teleutospores. 

P. ipomeae Cooke. On Ipornea in U.S. America and S. Africa. 

P. bunii (I). ('.). On ('arum Dulbocattanum and Pimpinella Sa.nfraya 
( Britain). 

P. smyrnii Biv. On Smyrnum Olmatrum. (Britain.) 

P. trollii Karst. On Aconitum Lycoctonum and Trollius europacus. 

P. valerianae Carest. On Valeriana officinalis and Centranthut 
Calcitrapa. 

P liliacearum Duby. On Or nit hoy alum, Scilla, and (layea. (Britain.) 

(5) Teleutospores alone produced ; they hibernate in dead host- 
remains ( Mieropuccinia , Schroet.) : 

Puccinia fusca (Relhan.). (Britain and U.S. America.) 
Anemone-rust. The brown spore-patches of thi§ fungus occur on 
various species of Anemone, Thcdiet rum, and Pulsatilla. Attacked 
plants of Anemone nemorosa (Fig. 190, <> and 7) have their leaves 
much altered, the petioles being abnormally long and the laminae 
much thickened, with narrowed segments, and conspicuously pale- 
green. The teleutospore-patches form chocolate-brown spots on 
the lower surface of the leaf, and stripes on the leaf-margins. 
Flowers are rarely developed on diseased plants ; Fentzling, 
however, found flowering plants with aeeidia on the leaves ; 
three of the perianth-parts being stunted. The same investi- 
gator found a few anatomical changes in deformed plants ; in 
petioles the middle one of the three vascular bundles normally 
present was larger than those on each side of it; in the dis- 
eased lamina the parenchyma-cells were enlarged, while inter- 

1 Dietel, Iledmgia, 1S!M, |>. 291 ; also Zeitxchriit f. Pfanvnkmnhhtiten, 1 SO.'l, 
p. 258. 


PUCCINIA. 


357 


cellular spaces were more numerous and also larger. Other 
minor differences are also given, but there seems to have been 



Fig. 190. — Anemone-Rust. 2 and 3, Normal plants ol Anemone ranunculoid.es. 
4, Aecidium punctatum on Anemone ranunculoides ; aecidia on the lower surface 
of the leaf ; the plants are abnormally elongated, and the leaf-segments aie 
smaller 6 and 7, Puccinia fused on Anemone nemorosa ; the plants remain small, 
6 is completely deformed,' 7 partially. 1 and 5, Aecidium teucospermum on 
Anemone nemorosa ; the plants are abnormally elongated and the leaf-segments 
smaller, (v. Tubeuf del.) 


358 


UREDINEAE. 


some confusion between plants infested with this Paccinia and 
those with species of Acculium. The changes induced on 
anemone by either Acculium Icucospermum D.C. or Aec. punctatum 
I’ers. are quite distinct (Fig. 190). 



Fir,. 191. — Puccinia ribu on Red Cu rran t (Ribf* rubrum). Teleutosporo-patches 
on leaves and fruit, (v. Tubeuf phot.) 

P. singularis Magn. Ou Anemone ranunculoid.es in Austria and 
south-east of Europe. The teleutospore germ-pore is situated at the centre 
of the lateral wall of the lower cell, thereby distinguished from that of 
/’. fusca, 

P. atragenis Haussm. On Atragene alpina. 

P thalictri Chev. On species of T/utlictrunu (Britain and l T .S. 
America.) 


PUCCI NIA. 


359 


P. Fergussonii Berk, et Br. On Viola palustns, etc. (Britain and U.S. 
America). 

P. alpina Fuck. On Viola biflora. 

P. geranii-sylvatici Karst. On Geranium sylvaticum A (U.S. America.) 

P. Morthieri Korn. On Geranium. # 

P. Holboelli (Horn.). On Arabis Holboelli and Erysimum narcissi folium 
in Denmark and U.S. America. 

P. drabae End. On Draba aizoides. (U.S. America.) 

P. dentariae (Alb. et. Schwein.). On Dentaria bulbifera and D. 
enneaphylla , causing pustule-like outgrowths on the leaves. 

P. ribis (D. C.) Currant-rust. On Ribes rubrum, R. nigrum , R. alpinum, 
R. Grossularia, and R. petraeum (Britain and U.S. America). (Fig. 191.) 

P. saxifragae Schleclit. On Saxifraga. (Britain and U.S. America.) 

(P. Pazschkei Dietel. On Saxifraga elatior and S. Aizoon.) 

P. rhodiolae B. et Br. On Sedum rhodiola. (Britain.) 

P. sedi Korn. On Sedum elegans. 

P. aegopodii (Schum.). On Umbelliferae, e.g. Aegopodium, Astrantia, 
and Peucedanuni. (Britain.) 

P. enormis Fuck. On Chaerophyllum aureum. 

P. asarina Knze et Selim. On Asarum. (Britain.) 

P. rubefaciens Job. On Galium boreale in Scandinavia and U.S. America. 

P. campanulae Carmich. On Campanula and Jasione. (Britain and 
U.S. America.) 

P. conglomerata (Str.). On Homogyne alpina. 

P. expansa Link. On Adenostyles and Senecio. 

P. virgaureae (D. C.). On Solidago. (Britain and U.S. America.) 

P. cardui Plowr. On Carduus lanceolatus , and C. crispus. (Britain.) 

P. Andersoni. B. et Br. On Carduus heterophyllus. (Britain.) 

P. bellidiastri (Ung.). On Bell idiast rum. (The aecidium on the same 
host belongs to Puce, firma Diet.) 

P. adoxae D. C. On Ado.va moschatellina. (Britain and U.S. America.) 

P. betonicae (Alb. et Schwein.). On Betonica officinalis and Stachys 
recta. (Britain.) 

P. Schneideri Schroet. On Thymus Serpyllum. (Britain.) 

P. scillae Lk. On Scilla bifolia in Hungary. 

P. tulipae Schroet. On Tulipa Gesneriana. 

P. Prosti Moug. On Tulipa sylvestris and T. Celsiana in Italy and 
F ranee. 

P. Schroederi Pass. On Narcissus poeticus. 

(6) The teleutospore-s germinate on the living plants, and again 
produce teleutospores. All other forms of spore are absent. ( Lepto - 
puccinia, Schroet .) : 

Puccinia malvacearum Mont, occurs on various Malvaceae. 

•Barclay ( Annals of Botany, v. , p. 27) describes and figures a car. himalensis 
on Geranium nepalense. 


360 


UREDINEAE. 


This rust is indigenous to Chili, and was introduced into France 
about 1868, whence it rapidly extended throughout the whole 
of Europe, and during the last ten years has made its appear- 
ance in the United States. In many places it has completely 
exterminated both wild and cultivated mallows, and rendered 
the cultivation of garden hollyhocks impossible. It appears in 



Fin. 192. — Puccinia malvacearum. Mallow loaf, with telcutoM>ore*8ori. Three 
teleutospores, one germinating, (v. Tubeuf del.) 

May or June on the leaves, stems, and petioles of the host ; 
all are more or less deformed, and the leaves may in severe 
cases wither up long before the flowers appear. Sponging 
with a solution of permanganate of potash (two tablespoonfuls 
in one quart of water), has been found an effective remedy. 

P. Sherardiana Ktim. On mallow in America. 

P. heterogenea Lager. On hollyhock in South America. 

P. anemones-virginianae Schwein. On Anemone. (U.S. America.) 


PUCCINIA. 


361 


P. thlaspeos Scliub. On Thlaspi alpestre and Arabis hirsuta 

P. spergulae D. C. On Spergula. (U.S. America.) 

P. arenariae (Sebum.). On Alsineae and Sileneae, e.g. cultivated Dianthus 
barbatus. (Britain and U.S. America.) 

P. chryosplenii Grev. On Chrysosplenium. (Britain.) 

P. circaeae Pers. On Circaea. (Britain and U.S. America.) 

P. buxi D. C. On Buxus sempervirens. (Britain.) 

P. umbilici Guep. On Umbilicus. (Britain.) 

P. valantiae Pers. On Galium. (Britain and U.S. America.) 

P. asteris Duby. (Britain and U.S. America.) • On Aster, Artemisia, 
Achillea, Cirsium, Scabiosa, Doronicum. Plowright regards P. millefolii 
Fckl. on Achillea as a distinct species. 

P. veronicae (Schroet.) (Britain). -1 

P. veronicarum D. C. (Britain and U.S. America). j-On Veronica. 1 

P. albulensis Magn. ) 

P. glechomatis D. C. On Glechoma {JVepeta). (Britain and U.S. America.) 

P. annularis (Strauss). On Teucrium. (Britain.) 

Hemileia. 

Hemileia vastatrix, Berk, et Br. This occurs on the leaves of the coffee 
plant in Ceylon, Java, and Sumatra. It causes a very destructive disease. 
Sadebeck recommends as remedies : (1) Removal of infected leaves and 
their sterilization by dilute acids or Bordeaux mixture. (2) Spraying 
the beds with Bordeaux mixture, so as to kill the spores which have 
fallen there. 

Several genera which do not occur in Europe may be mentioned here, 

viz.: Uropyxis, Diorchidium, Chrysospora, and Sphaerophragmium ; also 
Masseella, Phakospora, and Schizospora. 3 They contain but few species, 
and none of practical importance. 

Triphragmium . 4 

Teleutospores tliree-c^llecl ; one cell is attached to the sporo- 
phore, and carries the other two ; each cell has one or more 
germ- pores. 

Triphragmium ulmariae (Schum.). (Britain.) Uredospores 
and teleutospores produced on the same plant, Spiraea Ulmaria, 
The teleutospore-patches are dark-brown, the uredo-sori reddish- 
yellow, while the pycnidia (so-called spermogonia) are yellowish 

1 Distinction, see Magnus, Ber. d. deutsch. botan. Wes., 1890, p. 167. 

2 Sadebeck, Forstl-naturwiss. Zeilschri/t, 1895. M. Ward, Sessional Papers 2 

xvii., Colombo, 1S81. 

3 Dietel, Berichte d. deutsch. botan. Ges., 1895, p. 332. 

4 Bibliography and Revision, by G. Massee, Grevillea, xxi. , 1893, p. 111., 


362 


UREDINEAE. 


points. The so-called aecidia are really a form of uredo-sori ; 
they occur as thick cushions and cause thickening or twisting 
of the leaves and petioles. 

T. filipendulae (Lascli.) (Britain). On Spiraea Filipendula. 

T. echinatum Lev. occurs on Meum ; teleutospores alone are known 
(U.S. America). 

T. clavellosum Berk. On leaves of Aralia in the United States. 

Phragmidium. 

Teleutospores multicellular, the individual cells forming a 
single series ; they show a variable number of germ-pores. The 



Fif;. 1!»3 . — Tnphragmium ulmaruu on 
Spiraea Ulmaria. Germinating tcleuto- 
spore, with proraycelia and sporidia. 

(After Tulasne.) 

teleutospores are produced in loose patches. The aecidial patches 
have no covering, but are surrounded by club-shaped paraphyses. 
The genus frequents only Kosaceae. 

On species of Rosa : 1 

Phraginidium subcorticium (Schrank.). Teleutospores, uredospores, and 
aecidia on leaves of wild and cultivated roses. (Britain and U.S. 
America.) 

Phr. tuberculatum J. Mull. All the forms of spore occur on Rosa 

canina. 

Phr. fusiforme Schrot. [Phr. rosae-alpinne (D.C.)]. On Rosa atpina 
(Britain). 

Phr. speciosum (Fr.). On North American roses. 

Phr. devastatrix Sor. On roses in Asia. 

1 J. Muller, “Die Rostpilze d. Rosa. u. Ruhus-arteu,’’ Ber. <i. deutsch. 
bolan. Ocs . , 188.“). 


PHRAGMIDIUM. 


363 


On species of Potentilla : 

Phr. fragariastri (D. C.) (Britain and U.S. America). 

• Phr. potentillae (Pers.) (U.S. America). 

Phr. tormentillae Fuck. (Britain.) 

Phr. papillatum Dietel, from Siberia. 

Phr. nepalense Bard, and Phr. laceianum Barcl. in India. 


On species of Rubus : 



Phr. rubi (Pers.) {I’ hr. bulbosum 
Schlecht.) (Britain). 

Phr. rubi-idaei (Pers.). On leaves 
of raspberry. (Britain and U.S. 

America.) 

Phr. violaceum (Schultz) (Britain). 

Phr. rubi-miniatum J. Mull. 

Phr. albidum (Kuhn). 

Phr. quinqueloculare Barcl. 

Phr. octoloculare Barcl. 

Phr. Barclayi Dietel, from Hima- 
laya. 

Phr. gracile Farl., America. 

And other species. 

On Sanguisorba : 

Phr. sanguisorbae (D. C.). On 
Sanguisorba minor. (Britain.) 

Phr. carbonarium (Schlecht.) 

(Britain). This species has also 
been placed in a separate genus 
Xenodochus. It occurs on San- 
guisorba. Uredospores are want- 
ing ; the teleutospores form firm 
black crusts ; the aecidiospores 
form chains ; and the paraphyses 

are club-shaped. Diseased leaves and petioles are thickened and 
bent. Wakker’s investigation showed : a slight enlargement of 
parenchymatous cells and rupture of epidermis on spore-formation ; 
a diminution in the intercellular spaces and in formation of 
collenchyma and sclerenchyma ; a suppression of all production 
of chlorophyll and calcium oxalate. 


Fig. 195. — Phragraidium rubi from Rubus 
fruticosus. One spherical immature te- 
leutospore, and two well-developed and 
germinating ones. (After Tulasne.) 


Melampsora. 

Teleutospores dark and unicellular, in some cases multi- 
cellular by formation of new walls, generally in a vertical 


3G4 


UREDINEAK. 


direction ; their sori form dark spots which break out from 
beneath the epidermis. The yellow uredospores have a coat 
beset with fine spines, and are given off from sori which may 
or may not be enclosed in a peridium. The sori of the 
aecidium-stage have no peridium, and are known under the 
generic name of Caeoma ; they frequently occur on other hosts 
than those of the teleutospores. Pycnidia are produced in little 
yellow patches. 

Melampsora tremulae Tul. (Britain). The sori of uredo- 
spores appear as little yellow protuberances on leaves or young 
shoots of Populus tremula. The dark-brown patches of teleuto- 
spores appear later on the under epidermis, and where they 



Fio. 196 . — Catomn pinitorquum. Section showing four pycnidia, from one 
of which (»p) numerous conidia are being discharged. Ctwomn-patches are 
developing beneath the cortical layer, as yet unbroken. (After R. Hartig.) 


occur in large numbers, an early fall of the leaf may result. 
The teleutospores hibernate in dead leaves on llie ground. In 
spring the sporidia germinate and infect young shoots of Pi tuts 
sylvestris, producing the disease known as Caeoma pinitorquum d 
This disease attacks pine-seedlings, appearing generally on 
the needles. It is most frequent in plantations from one to 
ten years old, rarer in those of ten to thirty years, and not 
as yet observed in older. Pinus sylvestris is most commonly 
attacked, but it has also been observed on Pinus montana in 
Jutland. After formation of the Caeoma -patches, the young 
thin shoots generally die off, but thicker ones become twisted 
at the place attacked, whence the name “ pine-twister ” commonly 
given to this disease. If the leading shoot be attacked, the 
seedlings may succumb altogether. The disease develops rapidly. 


R. Hartig, II irh/iip Krankhritrn < I . I I'oM/hi (»»«*-, 1 ST 4. 


MELAMPSORA. 


365 


particularly in a damp and cold spring, and may prove very 
destructive if it appears for several years in succession. The 
mycelium evidently perennates in pine-shoots, and produces 
new Caeoma - patches year after year till death of the host results. 
It grows intercellularly especially in the rind parenchyma, but 
also in the medullary rays of wood and bast ; the contents 
of the host-cells are absorbed by means of short lateral haustoria. 



Fig. 197. — Caeoma pinitorquum. Portion of Catoma - patch (enlarged). /, Cortical 
cells partially absorbed or much compressed ; b, basidia from which spores (c) are 
abjointed in succession : the younger with delicate walls and separated by 
membranous lamellae, which disappear on formation of the spore-coats (d). 
(After R. Hartig.) 


The pycnidia are produced at end of May or beginning of 
June, between the epidermal cell- wall and the cuticle of green 
twigs ; before breaking out they may be observed externally 
as light patches on the shoot. The Caeoma - patches develop 
later in the second or third layer of the rind-parenchyma 
(Fig. 196). In each patch the spores are produced serially from 
short stalks to the number of twenty or thereabout, and ultimately 
escape about June, when the cells of the parenchyma and 
epidermis are ruptured. At first the spores are connected 
together by intermediate cells which are afterwards absorbed 
(Fig. 197). The mature spores are globose, oval, or polygonal 


366 


UREPINEAE. 


in shape, yellow in colour, and their outer coat is beset with 
spiny projections. The stalk-cells grow out into elongated tubes, 
after completion of spore-formation. In the vicinity of the 
scar of a Crtgowwi-patch, the twig turns brown and its tissues 
become permeated with resin, while the tissues underlying the 
patch die even into the pith. 

Hartig’s 1 investigations show that this same Melampsora causes 
Caemaa laricis on the needles of the larch. Plowright 2 also 
produced a similar Caeoma- form from Melampsora betulina, and 



Fio. 198. — Af<lamp*ora betulinn. Tcleiitoepore-sorus, with many of the spores 
producing nromvcelia and sporidia (*). r, Mycelium ; p, parenchyma ; < . portion 
of ruptured epidermis. (After Tulasnc.) 


succeeded in re-infecting Befula alba from Caeoma laricis. 
Rostrup obtained Caeoma mercurial is by infecting Mercurialis 
with Mel. tremulae ; yet this may have happened because two 
different species of Melampsora occurred on the aspen leaves. 
Klebahn 8 was successful in infesting Populus tremula with 
Caeoma laricis but did not succeed with the birch. 

1 R. Hartig, AUerjem. Forst. tt. Jayd-zeitung, 18S.‘). 

2 Plowright, “ Impfversuche in. Rostpil/.en," Z> ilxrhrifl f PJtanzenkranl'hcitai, 
1891. 

:1 Klebahn, Zeituchrift f. Pfianzenkraiikhtiten, 1894. 


MELAJI PSORA. 


367 


The patches of Caeoma laricis Hartig , 1 appear as golden-yellow 
cushions on the underside of the needles. The sporophores from 
which the aecidiospores are abjointed, form the centre of the patch, 
the periphery being occupied by numerous sterile threads, which 
grow out as long paraphyses ; it may so happen that the whole 
cushion consists only of these last. The formation of Caeoma- 
patches is preceded by that of little pycnidia (spermogonia), 
which break out from under the cuticle. The mycelium lives 
intercellularlv, and dies after the shedding of the Caeoma- 
spores. 

Melampsora betulina (Pers.) (Britain and U.S. America). 
Uredo- and teleutospores occur on the leaves of the birch 
( Betula alba). Plowright 2 found from arti- 
ficial infection that this species produced 
Caeoma laricis on the needles of Larix 
europea. A second form of Caeoma laricis 
was obtained by Hartig, both from infec- 
tion by Mel. tremulae Tub from the aspen, 
and by Mel. populina Jacq. from the black 
poplar. 

M. populina (Jacq .) 3 (Britain and U.S. 

America). Uredo- and teleutospores found 
on Populus nigra and P. bal.samifera. 

M. populina and M. tremulae are probably identical, for Hartig 
has found the same Melampsora on black and balsam poplars 
as on aspen, and in each case he produced Caeoma laricis by 
means of the uredospores. Schroeter states that the Melampsora 
of Populus nigra produces Caeoma allii of Allium. 

M. aecidioides I). C. (Britain). Uredo- and teleutospores on 
leaves of silver poplar ( P. alba and P. canescens ). Plow- 
right connects with it a caeoma- form on Mercurialis ( Caeoma 
mercurialis). Schroeter states that the Melampsora of Populus 
tremula produces Caeoma mercurialis. 

The Melampsorae of Willows were until recently grouped 
under a collective name, M. salicina ; several species are now 
recognized, others require verification. 



Fig. 199. — Melampsora 
betulina. Portion of a 
uredospore-sorus. (After 
Tulasne.) 


1 R. Hartig, Wichtige Krankheiten cl.’ Wcddbaumen, PL V. 

2 Plowright (loc. cit. ). 

3 R. Hartig, Botan. Centralblatt, xlvi., 1891; “ The leaf-rust of cottonwoods,” 
U.S. Dept, of Agriculture Report, 188S, p. 390. 


368 


UREDINEAE. 


M. salicis-capreae (Pers.) (Britain and U.S. America). 
( icdo- and teleutospores on leaves of Salic Caprea and several 
species. According to Rostrup, Caeoma cuonymi (Gmel.) 
is a stage of this. 1 

M. Hartigii I hum. - (M. epitea Thiim.) (Britain and U.S. 
America). 1 redo- and teleutospores on leaves of Salix pruinosa. 
S. daphnoides, S. viminalis, etc. Rostrup regards C. ribesii Lk. 
of Riles as a caeoma- form. 



Fit,. 200.— Htlamptora mhcit-eapmu . Section through lent of Satis Caprea. 
with a uredospore-sorus on the lower epidermis ; on the upper side a teleutosporc- 
eonis is in process of development, but is as yet completely closed over. (After 


M. repentis Plowr." 1 redo- and teleutospores on Salic repen*. Caeoma 
on Orchis maculata. (The Caeoma orchidis of other orchids is probably 
identical with this one.) 

M. arctica Rostr. on Salic herbacca, S. glauca, and S. groenlandica' in 
Greenland. 

M. mixta oSchlecht). (Britain). I lie related Caeoma is unknown. 

rhtimen also gives M. Castagnei Thiim. on S. amggdalina. 

M. vitellinae D. C. on Salic fragi/is is said by Schroeter to have its 
Caeoma, on Oalanthus nivalis (Britain). 

I lie rusts of cultivated willows are very detrimental to them 

' M. salicis-capreae (M. caprearum D.G.) is divided by some authorities into 
M. fannosa (Pers.) and M. epitea (Kze. et Schm.). 

-bee ThUmen, "Mel. salicina," MiUheilungcn an* d. forstlieh. Versuchsiotsen 

Oesterreich, 1879. 

3 Plowright (loc. cit.). 


MELAMPSORA. 


369 


and cause great damage. The yellow 
sori appear in large numbers on the 
lower surface of the leaves, which 
wither prematurely, especially towards 
the ends of shoots (Fig. 201). 1 he 

teleutospores hibernate on fallen leaves, 
hence such should be raked together 
and burnt. Salix pruinosa is found 
to be much more sensitive to attack 
than S. pruinosa x daphnoides, whose 
leaves are more hairy, a property 
which seems to protect them from 
spores. 

The following species have only 
uredospores and teleutospores, related 
Caeoma - forms being unknown : 

M. lini (Pers.) (Britain and U.S. 
America). Flax-rust. The uredo- and 
teleutospores occur together on Linum. 
This may inflict serious damage in 
fields of cultivated flax. 

M. sorbi (Oudem.). On leaves of 
Pyrus Aucuparia and P. torminalis. 
Dietel 1 2 has recently placed this as 
the single species of a new genus 
Ochrospora. The light-yellow spores 
are at first one-celled, but before 
the death of the host-leaves they 
divide into four (rarely three) cells, 
each of which gives off a sterigma 
with a single sporidium. In these 
points the spores follow the develop- 
ment of (Jolcosporium ; the sporidia, 
however, are quite different, they are 
spindle-shaped, 22-2 5 m long and 8/x 
broad. 


1W:1 


/\ 


•v- 




Fig. 201 .—Melampsora Hartigii on Salix 'pruinosa. The upper leaves 
have already withered and curled up, the lower, though as yet un- 
changed, are beset with the point-like sori. (v. Tubeuf del.) 

1 Berichte cl. cleutsch. botan. Ges., 1895, p. 401. 

2 A 


370 


UREDINEAE. 


M. ariae (Schleich.). On leaves of Pyrus aria. 

M. padi (Kunze et Schum.). On leaves of Prunus Padua. (Britain.) 

M. hypericorum (D.C.). On Hypericum. (Britain.) 

M. pustulata (Pers.). On Epilobium. (Britain and U.S. America.) 

M. circaeae (Schum.). On Circaea. (Britain.) 

M. vaccinii (Alb. et Selim.). On leaves of Vaccinium. (Britain and U.S. 
America.) 

M. pirolae (Gmel.). On Pyrola. (Britain and U.S. America.) 

M. sparsa Wint. (U.S. America). On Arctostaphylos alpina (also A. 
officinalis acc. to Rostrup). 

M. carpini (Nees.). On leaves of hornbeam. 

M. galii (Lk.). On Galium. 

M. (Thecopsora) agrimoniae (D.C.) On Agrimonia. 

M. vernalis Niessl. Teleutospores only on Sa.rifraga granulata. 

M. helioscopiae (Pers.). On Euphorbia. (Britain.) 

M. euphorbiae-dulcis Otth. 

Melampsorella. 

The unicellular teleutospores are developed in the cells of 
the epidermis and form reddish patches. The patches of 
uredospores are enclosed in a peridium. 

Melampsorella cerastii (Pers.). Uredo- and teleutospores on species of 
Stdlaria and Cerastium. (Britain and U.S. America.) 


Calyptospora. 

The teleutospores are developed inside the epidermal cells, 
and are divided into four cells by vertical septa. The aecidia 
have large peridia. The pycnidia are small and precede the 
aecidia. 

Calyptospora Goeppertiana Kuhn. 1 (U.S. America). The 

common disease of cowberry ( Vaccinium Vitis-ldaca) caused by 
this parasite is shown externally by a very marked swelling 
and elongation of the shoots (Fig. 202). Diseased plants 
elongate conspicuously above their neighbours, and in this way 
distribution of their spores by wind is facilitated. The mycelium 
hibernates in the cortical tissues, and maintains itself for years. 
It grows intercellularly, sending haustoria into the cortical cells. 
As a result of its presence, cell-growth is much accelerated, 
and a marked thickening of attacked twigs frequently occurs; 

1 B. Hartig, Lehrhvch < I . Ra umbaukheitcii, i. Aufl. j>. 56 and PI. II. (The 
‘2nd edition and the English translation are somewhat abridged.) 


CALYPTOSPORA. 


371 


intercellular spaces become enlarged, and the contents of all 
cortical cells, except those of the epidermis, takes on a red 
colour, whereby the young shoots have at first a delicate rose- 
red colour, though they afterwards turn brown. The lower 
leaves have a similar red colour, but shrivel and fall off early, 
while the upper ones develop normally and remain attached. 



Fig. 202. — Calyplospora Goepper liana. Normal and malformed shoots of 
Vaccinium Vitis-Idaea. (v. Tubeuf phot.) 


Shoots infected one summer show the symptoms in the 
following year. The swelling is confined to the basal part of 
a year’s growth, and the apices of shoots remain normal to all 
external appearance, although permeated with mycelium. Hartig 
has explained this by assuming that the fungus-mycelium only 



372 


URED1NEAE. 


influences young cells attacked by it during their period of 
growth, whereas cells already in the adult condition remain 
unaffected. 

Inside the diseased shoots a well-developed mycelium will 
be found between the epidermal cells, and nourished by baustoria. 



Fio. 203 . — Calyvlotpora Gorppertiana. Section through epidermis amt cortical 
parenchyma of a diseased shoot of Vo rani um . The mycelium is intercellular, but 
swollen branches penetrate the cell-walls and lwcomc sac-like haustoria. The 
hyphae under the epidermis become considerably swollen, and give off into the 
cells either haustoria (b) or the sac-like processes (c, c), which become the motlier- 
ceils of the teleutospores. X 420. (After R. Hartig.) 

Tbe spores originate from processes M the mycelial hyphae, 
which bore their way into the epidermal cells, and swell up 
inside to form spherical sacs. The cells thus entered turn 
brown, and are filled up by four to eight cells produced from 
the sac-like processes of the mycelium (Fig. 203). From each 
cell of this kind a four-celled teleutospore is formed and hiber- 
nates in situ. In spring the teleutospores emit a process through 
the outer wall of the epidermal cell, and this, after division 
by cross-septa into four cells, becomes a promycelium with short 
sterigmata, from each of which a single sporidium is abjointed 
(Fig. 204). The sporidia germinate, as Hartig proved, about the 
middle of May, on young needles of silver fir (Abies jwetinata). 
By the middle of June the mycelium is distributed through 
the intercellular spaces, and forms aecidia with long white sac- 
like peridia on the under surface of the leaf (Figs. 205, 20G) 
The aecidiospores escape on rupture of the peridium and the 


CALYPTOSPORA. 


373 


host-epidermis, to germinate on the epidermis of another cowberry- 
shoot. The germ-tube either enters by a stoma, or forms an 
adhesion-disc and sends out a process from this through the 
epidermis. 



Fig. 204. — Diseased stem of Vaccinium in a 
Later stage than Fig. 203. In each epidermal 
cell (a, ft) six mother-cells have been formed, 
each subdivided into four teleutospores. 
Promycelia (b) have developed from many of 
the latter, and are in process of abjointing 
off the sporidia from lateral sterigmata. 
X 420. (After R. Hartig.) 



Fig. 205. — Calyptospora GoeppeHiana. 
Aecidia on the under surface of needles 
of Silver Fir. (v. Tubeuf del.) 



Fig. 206. — Aecidium in a needle of 
Silver Fir (much enlarged), b, Series 
of aecidiospores and intermediate cells. 
c , Germinating aecidiospores. (After 
R. Hartig.) 


This aecidium is also found on Abies cephalonica in Upper 
Bavaria. 

Barclayella deformans Diet. 1 This has been found in the Himalaya 
region on needles and young twigs of Picea Morinda ( Smithiana ). Teleuto- 
spore-sori are developed, accompanied by distortion of the host. Aecidia 
and uredospores are unknown. 


’Barclay, “On a Uredo of the Himalaya Spruce-fr.“ Calcutta, 1886; and 
Hedwigia, 1891. 


374 


UREDINEAE. 


Coleosporium. 


The teleutospores form a soft, reddish, waxy cushion, and 
germinate in situ producing four-celled promycelia ; in these 
respects they exhibit great resemblance to Auricularia. Uredo- 
spores are developed in chains. The aecidia, as yet known, 
have a distinct peridium. 

Many species infect the needles of pine trees and produce 
aecidia known by the generic name Peridermium ; other species 
also known as Peridermium and living on bark are really 
species of Cronartium. The species here mentioned with their 
Peridermium - form on pine-needles, so much resemble one an- 


other as to be almost indistinguishable, and 
the question arises whether they are really 
species, or only varieties due to difference 
of substratum — habitat-races. 



Coleosporium senecionis (Pers.). (Britain.) 
The sori are produced on leaves and stems of 
various species of Senccio (without doubt on 
S. vulgaris, S. sylvaticus, S. viscosus). The 
uredospores are shed in June from yellow 
spots. The teleutospores follow later on 
dark-red patches, there they hibernate and 
in spring produce a four-celled promycelium, 
each cell of which gives off a sterigma with 
one sporidiuni. The latter germinate on 
needles of Pinus sylvestris. A mycelium is 
formed in the intercellular spaces of the 


FlO. 207 . — CoLeoxporium 
junction i* on a bifoliar 
«pur of PinuA 9ylvt*tri*. 
I'eridia and scar« of the 
pycnidia arc shown, (v. 
Tubcuf del.) 


needles, and, nourished by means of haustoria sunk into the 
host-cell, perennates and produces crop after crop of aecidiospores. 
Hyphae are produced in such numbers that the cells of the 
needle-parenchyma are tightly pressed together, and those 
adjacent to pycnidia and aecidia turn brown, secrete resin, and 
die. The needles themselves, although filled with mycelium, 
remain on the tree till the time of their normal fall. 

Pycnidia are 1 developed by April or May under the cells of 
the epidermis. They are little obtuse cone-shaped enclosures 
appearing as brownish-yellow spots scattered over the inner 
faces of the needles. On attaining maturity they rupture the 
host-epidermis and give out their conidia. 


COLEOSPORIUM. 


375 


The aecidia are produced amongst the pycnidia on needles 
two or three years old ; they have long white peridia and 
are known as Pcridermium oblongisporium Fuck. The aecidio- 
spores are yellow when mature, and originate in chains, which 
in the earlier stages of development consist of intermediate 
cells and spores, but the former gradually disappear (Fig 208). 
The spores have an average length of 30'5/x and breadth of 



Fio. 20S . — Pcridermium pin i (Coleosporium scnecionis). Portion of an aecidium 
with basidia ( b ) giving off spores and intermediate cells (d ) ; outside the 
peridium ( p ) other basidia (<) with club-shaped ends force up the epidermis; 
", the thick mycelium in the leaf-parenchyma. (After R. Iiartig.) 


20 , 01 ; in form they are generally longish-oval, few being round; 
the spore-coat is moderately thick. Aecidiospores are capable 
of immediate germination, and produce £7rafo-patches on Senecio 
by June. 

The uredospores have an average length of 2 8 ‘5/u., and 
breadth 1 5*5/x ; they are generally oblong, with a moderately 
thick coat beset with spiny warts. 


376 


UREDINEAE. 


Klebahn and Fischer 1 assert that several other species of 
Coleosporium produce their aecidium-stage on Finns sylvestris. 

C. euphrasiae (Schum.) (Britain). Uredospores produced from 
reddish-yellow, teleutospores from orange-red patches during 
July and August on various Rhinanthideae ( Rhinanthus major, 
R. minor, Bartsia Odontites, and Euphrasia officinalis). The 
spores from Rhinanthus germinate on needles of Finns sylvestris 
and produce an aecidium called Peridermium Stahlii Kleb. 
The aecidiospores of F. Stahlii average 2 Gm in length, 19'5 /a 
in breadth, and are round or shortly oval, with a coat and 
markings finer than those of F. oblongisporium. The uredo- 
spores average 22 n x 15'5/x; they are irregular and somewhat 
angular, with a thin finely marked coat. 

C. melampyri (Ifeb.) (Britain). Uredospores on Melam- 
pyrvm (certainly on M. pratense). The aecidia — Fcriderrnium 
Soraucri Kleb. — follow after a year on needles of Finns sylvestris. 
The spermogonial pycnidia alone are developed in the summer 
of infection. 

C. tussilaginis (l'ers.) (Britain). This Coleoqjorium is found 
all summer on the underside of leaves of Tussilago farfara, 
the uredospores forming yellow patches, the teleutospores darker- 
coloured ones. Aecidia are produced on needles of Finns 
sylvestris, and are known as Peridermivm F/oicrighfii. Pycnidia 
and aecidia are formed in the summer following infection. 
The aecidiospores average 25'5/x x 19/w and are shortly oval 
or round, with coats and markings more delicate than those 
of F. Stahlii. The uredospores average 26/u x 1 9/t and are 
roundish oval with somewhat firmer and thicker coats than 
those of C. euphrasiae. 

Klebahn’s infections of Fetasites with aecidiospores from Finns 
gave no result. 

C. inulae Kunz. Spores of this obtained by Fischer 2 from 
Inula VuiUantii and I. Helen ium produced Peridermium Klebahn i 
Fisch. on needles of Finns sylvestris. 

C. sonchi (Bers.) (Britain and U.S. America). Klebahn 
considers this as a provisional species including a number of 
imperfectly investigated forms whose uredo- and teleutospores 

1 Brrirhte d. deutsch. hot an. G<s. , 1 SO 4 ; Zeitschri/t f. P/laitzenkraiikhfitfn, 1894, 
anil 1895, p. 73. 

- liotan. Centralhlall , lix., 1894, p. 1. 


COLKOSPORIUM. 


377 


occur on various species of Sonchus (without doubt on S. 
arvensis). Aecidia are unknown. He relates it to Peridermium 
Fischcri Kleb. on needles of Pinus sylvestris. 

C. synantherearum Fr. A provisional collective name for 
aecidia on Adenostyles, Petasites, Cacalia, Senecio, etc., the life 
history of which is as yet unknown. 

C. campanulae (Pers.) (Britain). Uredo- and teleutospores 
on Campanulaceae ( Campanula and Pliyteuma). The aecidial 
form is Peridermium Rostrupii on pine-needles. 

C. pulsatillae (Str.). Uredo- and teleutospores on Anemone 
Pulsatilla and A. pratensis. Aecidia unknown. 

C. ipomoeae (Schwein). Uredo- and teleutospores on species 
of cultivated Ipomoca in United States. Aecidia unknown. 

Fischer 1 obtained pycnidia on needles of pine by infection 
with a Coleosporium from Campanula Trachelivm. 

Chrysomyxa. 

The teleutospores are formed closely together in yellow sori ; 
each spore consists of an acropetal series of cells, the distal 
one of which, without leaving the sorus, germinates to produce 
a promycelium of several cells. Uredospores are not always 
present. The aecidia have well-developed peridia. 

Chrysomyxa rhododendri (D. C.). 2 This is a common rust 
on the Alps where the Alpine-rose (Rhododendron ferrugineum and 
R. hirsutum) occurs. Immediately after the break-up of the 
winter little dark-red cushions of this rust appear on the under- 
side of the leaves. These contain the sori of teleutospores 
already partially developed during the previous autumn, and 
now r , after hibernation, ready to increase in size and to rupture 
the host-epidermis (Fig. 211). The teleutospores so exposed 
germinate without leaving the sorus, and produce four-celled 
promycelia, with sterigmata, from each of which a single 
sporidium is abjointed. The sporidia make their escape in 
June, and alighting on the unfolding needles of the spruce 
(Picea cxcelsa), they germinate at once and produce Aecidium 
abietinum, the blister-rust of the spruce (Fig. 212). 

An intercellular mycelium is developed in the spruce-needles, 

1 Botan. Centra/blatt, lix. , 1S94. 

2 De Bary, Botan. Zeitung, 1879. 


378 


UREDINEAE. 


and small yellow pycnidia are produced during July or 
August. The aecidia follow from August till September, 
occupying yellow zones on the otherwise green needles ; their 
white peridia project as much as 2 mm. above the surface of 
the needle, and dehisce by rupture of the apex. The aecidiospores 
are formed in large numbers and, carried by wind, reach leaves 
and shoots of alpine-rose where they immediately germinate. 
The resulting mycelium produces in September yellow clusters 
of uredospores on brownish spots on the lower epidermis of 
the leaves, and on the bark of last year’s shoots (Fig. 210). 



Flo. 209 . — Chrynomyxa rhndodendri . Twig 
of Rhododendron hirtutum with sori of uredo- 
apores on the lower epidermis, causing dis- 
coloured spots on the upper, (v. Tubeuf 
del.) 



The uredospores are yellow and ovoid, with granular protuber- 
ances on their coats ; they are developed in series from the sori. 1 
The disease may be further propagated during the same year 
by the uredospores. In districts where spruce does not occur, 
it is probable that these spores hibernate, and in the following 
spring produce germ-tubes which infect other alpine-rose leaves. 
It frequently happens that whole forests of spruce are so attacked 
by this fungus that many of the trees retain only a few 
healthy needles. Diseased needles die and fall in the summer 
of attack, so that the trees may be almost wholly stripped, 
and thereby suffer considerable damage. 

Chr. ledi (Alb. et Schwein.) 2 (U.S. America). This fungus 


1 Raciborski regards the L’rrrfo as a Cneoma-form. 
- Re Bary, Bolan. Zeitung, 1 879. 


CHRYSOMYXA. 


379 


occurs on Ledum palustre. It is difficult to distinguish from 
the preceding species, and causes the formation of similar aecidia 
on spruces in Northern Germany and other parts where Rhodo- 
dendron is not indigenous. Its uredospores are also capable 
of hibernating and of propagating the fungus where spruce is 
absent. 

Chr. himalayensis Barcl. occurs on leaves of Rhododendron 
arborcum in the Himalaya. 



Fig. 211. — Chrysomyxa rhododcndri. Teleuto- 
spore-sorus which has ruptured the lower epi- 
dermis of a leaf of Rhododendron hirsutum. The 
teleutospores are pluricellular, and one of them 
has germinated, giving a promycelium with 
sterigmata, from which little sporidia are being 
abjointed. (After De Bary.) 



Fig. 212. — Chrysomyxa rhododcndri 
on Spruce. The needles are beset 
with aecidia ; discoloured parts of 
them are shown black, the normally 
green being left white, (v. Tubeuf 
del.) 


Chr. abietis (Wallr.). 1 Needle-rust of spruce. This is parasitic 
on the spruce ( Piceci cxcelsa), and is found on the Alps up to 
an elevation of over 1700 metres. About the beginning of 
May the hibernating teleutospores produce promycelia and 
sporidia. The latter germinate at once, and the germ-tubes 
make their way through the epidermis into young unfolding 
needles. The mycelium is well-developed and lives inter- 
cellularly, sending haustoria into the host-cells; it contains 
yellow oil-drops, so that by the end of June needles contain- 
ing it exhibit yellow-coloured stripes. For the remainder of 
the year reddish-yellow elongated teleutospore-cushions are 

1 Reess, Botan. Zeitumj , 1865 ; Die Bostpilzformen d. deutschen Coniferen, 1869. 
Willkomm, Die m ikrosco pinch en Feinde den Walden, 1868. 


380 


UREDINEAE. 


formed, and in this condition the fungus hibernates, to develop 
further in the following spring. It is only in very dry cold 
winters that the needles dry up and fall off; as a rule they 
remain on the trees. About the beginning of May the spore- 
cushions break through the epidermis and give off multicellular 
teleutospores, which are as a rule branched. 
Thence arise the four-celled promycelia, with 
sterigmata, from which a single sporidium is 
abjointed. 

Diseased needles remain green except in 
areas inhabited by mycelium ; yet needle-cast 
soon follows liberation of the fungus-spores. 
Starch is laid up in large quantity in diseased 
needles during the first summer, but is com- 
pletely used up again by the mycelium for the 
formation of the teleutospore- patches. Spruces 
may suffer considerably from loss of foliage 
induced by this fungus, yet the risks are by 
no means so great as in the case of C/iryso- 
my.ra rhododendri where the whole existence of the plant is 
endangered. 

Uredospores are unknown for this species and an Arc id in m 
stage has not as yet been discovered. Ifeess has shown experi- 
mentally that the teleutospores germinate directly on spruce 
without intervention of an aecidial stage. 

Chr. piceae Bare. < )n needles of Picea morinda in India. 

Chr. empetri (Pers.) (Britain and U.S. America). Uredospores on 
Empetrum nigrum. Caeoma empetri (Pers.) is the aecidial form. 

Chr. pirolae (I). ('.) (Britain and U.S. America). Uredo- and teleuto- 
spores on Pyrola. Aecidia unknown. 

Chr. albida Kuhn. On liubus fruticosus in Germany and U.S. America. 



Fig. 213 . — Chrytomyxa 
abUti* on Picea excel m. 

The sori occupy the 
middle portion of each 
needle, which is in con- 
sequence yellow, while 
the apex and base are 
still green, (v. Tubeuf 
deL) 


Cronartium. 

Teleutospores unicellular and remaining attached together 
in the form of a long coiled process; they germinate in 
situ and give off sporidia. The masses of teleutospores arise 
on the place formerly occupied by a uredospore-sorus. The 
ovoid uredospores are abjointed from short stalklets enclosed 
in sori with a short peridium. Aecidia are developed on other 


CRONARTIUM. 


381 


host-plants, and several species produce blister-rust on the bark 
of species of pine. 

Cronartium asclepiadeum (Willd) (U.S. America). Uredo- 
and teleutospores occur on Cynanchum Vincetoxicum (perhaps 



Fig. 214 . — Cronartium asclepiadeum on Cynanchum Vincetoxicum. The uredo- 
sori show as spots, the teleutospore-sori as processes on the leaves, (v. Tubeuf 
del.) 


also on Gentianci asclcpiadea). The aecidial stage, known as 
Peridermium Cornui Eostr. et Kleb. produces a blister-rust on 
the bark of Pinus sylvestris. 



Brown spots may be found on the leaves of the Cynanchum 1 
during July, August, and September (Fig. 214). On examina- 
tion of the spots with a lens, the leaf-epidermis will be found 

1 A very common plant in Europe though not indigenous to Britain. (Edit.) 


382 


UREDINEAE. 


pierced by a circular opening under which lies the yellow 
uredospore-patch of the Cronartium enclosed in its peridium. 
The ovoid yellow uredospores have a coat beset with short 
spines and are abjointed singly from short cylindrical sporo- 
phores (Fig. 215). From the uredo-sorus there next arises a 
protuberance which lengthens till it forms an elongated slightly 
curved brown cone or column consisting of cylindrical teleuto- 
spores firmly built together (Fig. 215). The teleutospores 
germinate without becoming detached from the mass, and 
produce a four-celled promycelium with small sterigmata from 
which globular sporidia are abjointed. The sporidia on reach- 
ing the branches of Scots pine produce in its bark at first 
pycnidia, later aecidia. The pycnidia (spermogonia) give off 
yellow drops of liquid with a characteristic odour. The 
aecidia are yellow thick-walled sacs ; their spores are set free 
in spring and infect young plants of Cynanchum. 

Since the sporidia of the Cronartium- stage are shed by 
September, the fungus would seem to hibernate only in the 
form of mycelium in the branches of pine. 

The effects of this fungus on the pine will be considered 
along with those of Peridermium pini, another blister-rust 
of pine closely resembling this species (p. 411). 

Cr. ribicolum Dietr. Uredo- and teleutospores are developed 
towards the end of summer on leaves of various species of 
Ribes (e.g. Ribcs nigrum, rubrum, aurcum, alpinvm, sangvinrum, 
americanum, rotund if olium, sctosum, and Grossidaria). The 
aecidium-stage ( Peridermium strobi Kleb.) forms the blister-rust 
of the bark of Weymouth pine {Pious Strobus). Pycnidia 
appear in the summer of infection ; the aecidia a year 
later. Externally this bark-rust resembles that of Peridcnniuin 
Cornui and P. pini on the Scots pine. It may cause con- 
siderable damage to Weymouth pine both in nursery and 
plantation. 1 

It is probable that other two forms of Accidium are identical 
with this, viz., that on Pious Lambcrtiana in America, and 
P. Cembra especially in Russia. 

Cr. flaccidum (Alb. et Schwein.) (Britain and I’.S. America). 
Uredo- and teleutospores on Paconia, causing the leaves to dry 


1 Magnus ( Oartmflora , 1 X9 1 ) lias pointed out that both the Cronartium and 
the / J eridenniutn are unknown in America, the home of the Weymouth pine. 


CRONARTIUM. 


383 


and curl up. In some districts very common. Aecidial stage 

unknown. 


Gymnosporangium . 1 

Teleutospores bicellular and furnished with stalks which have 
gelatinous walls, so that the spores come to form part of a 
gelatinous mass . 2 The first-formed teleutospores are thick- 


Fig. 216 . — Gymnosporangium clavariaeforme. 1, 2, 3 , Stages in development of 
the spore-cushions. 4, 5, 6, Isolated spores (enlarged) ; 5 is thin-coated, the 
others are thick-coated. 7, Germinating spore with promycelium abjointing 
sporidia (#). 9, A germinating sporidium. (After Tubeuf.) 

walled, the succeeding ones are thin-walled. Uredospores do 
not occur. T(ie aecidia have a thick peridium. The teleuto- 

1 v. Tubeuf: (1) Centralblatt f. Balder, u. Farasitenkunde, 1891; with a review 
of the current Literature. (2) “ Infectionen mit Gymnosporangium.” Forstlich- 
naturwiss. Zeitschrift, 1893, p. 75. Woernle, “ Anatomische Untersuchungen d. 
durch Gymnosporangium-Arten hervorgerufenen Missbildungen, ” idem., 1894. 
American Literature, see p. 401. 

2 The gelatinous substance is obviously well-adapted to absorb rain-water 
and so facilitate germination of the teleutospores in situ ; the sporidia pro- 
duced are then carried off by rain or liberated after the cushions dry again. 



384 


UREDIXKAK. 


spores grow on needles and twigs of Coniferae, the aecidia on 
the leaves of various Rosaceae (Pomaceae). Five species occur 
in Germany, but there are many in America. 

Gymnosporangium clavariaeforme Jacquin. (Britain and 
17. S. America.) The mycelium of this species perennates in 
twigs of Juniper u.s communis. Infection is brought about by 
aecidiospores. In the following year a swelling of attacked 
places is evident, and this increases till death of the host 
ensues. In spring, about the beginning of April, little light- 
yellow cone-like structures break out on the swollen places. 



Fig. 218.— Longitudinal 
section of a s| tore -cushion 
of Gjnnno*f> 0 )tinvnim da- 
vitritvform*'. Somewhat 
diagrammatic. (After 
Woerale. ) 


P*' Fig. 217.— Section through a swelling on a sixteen year twig 
of Juniper attacked by Gymnoiporanf/ium in ita eighth year : 
three conical spore-cushions are indicated, also a cushion -acnr 
with the scar-tissue. (After Woemlc.) 


and during rain swell up into long club-shaped sporophores, 
containing long-stalked, spindle-shaped teleutospores, some thick- 
coated, some thin. The sporophores swell and ultimately form 
a common mass in which the teleutospores germinate. The 
spores have four germ-pores, each capable of giving off a 
promycelium with pointed sterigmata producing sporidia, which 
are cast loose and distributed by wind. 

Germination of sporidia takes place on leaves, cotyledons, 
petioles, and shoots of various Pomaceae, where they may 
induce swellings or curvature, often to a considerable extent. 


GYMN0SP0RANGIUJ1 . 


385 


Experimental infection with teleutospores of Gymnospor- 
angium cl avariacforme from Juniper vs communis gave the fol- 
lowing results : 


On Host-plant. 
Crataegus Oxyacantlia , 
Pyrus communis, 
Crataegus tomentosa, 
Crataegus Oxyacantlia, 
„ monogyna, 
Pyrus communis, 

Py rus torminalis, 
Pyrus Malus , - 
Amelanchier, - 


Crataegus Oxyacantlia, 

Crataegus granclijlorus, 
„ sanguinea, 

„ nigra, 

Cydonia vulgaris , 

Py, •us Aucuparia, 

Pyrus latifolia, 


Cydonia vulgaris, 


Crataegus nigra , 

Crataegus Douglasii, 
Pyrus Aria, 

Pyrus Aucuparia , 

Pyrus communis, 


Spore-form. 

; } (?) 


- R. lacerata, 


Authority. 

Plowright. 

Thaxter. 


J R. lacerata, - 

- Roestelia (J), - 

- pycnidia, 

- It. lacerata x, 

IR. lacerata and aecidia 

- 1 with long tube-shaped j-Tubeuf. 
( peridia, 

- )- It. lacerata, - - - „ 


Ih'itliay. 

’ll 

Oersted. 

Thaxter. 


only pycnidia, 
only pycnidia, 
f pycnidia and little 

( aecidia, - - - 

[ pycnidia and aecidia 

with long tube-shaped j-Peyritseh. 
[ peridia, - - - j 

(pycnidia and little 1 

\ aecidia, - - - / 



>> » » » 

- only leaf-spots, - „ 

- no result, - ,, 

( pycnidia and aecidia with ) 

( a long peridium, J 


Note. — Before the relationship of the teleutospore- forms was known, the 
aecidia were designated respectively : Roestelia lacerata on Crataegus, R. comuta 
on Pyrus Aucuparia, and R. pencillata on Apple. 


The most abundant germination of sporidia takes place on 
species of Crataegus, and pycnidia (spermogonia) may make 
their appearance within fourteen days after infection on little 
yellowish sticky spots on leaves and shoots. By the time conidia 
(spermatia) have made their appearance, deformation may be 
far advanced. I did not succeed either in procuring germination 
of the conidia, or infection by means of them. 


386 


UREDINEAE. 


The aecidia are developed about the beginning of June, and 
on Crataegus their peridia in dehiscing split up into very 
narrow lobes so as to form a bristly tuft over the mouth of 



each aecidium. On cultivating infected plants of Crataegus 
indoors, I found the peridia to develop quite abnormally; they 


GYMNOSPORANGIUM. 


387 


may be as long as 10 m.m. and are bent like a horn (Fig. 219). 
A similar case is described by Barclay 1 in which the peridia 
of aecidia on Rhamnus dalmrica were very long if produced 
in dry weather, but short if in moist weather. 2 

The aecidiospores are shed during the early part of June, 
and germinate at once on the bark of young juniper-twigs ; 
the mycelium growing thence into the spurs or branches to 
spread and hibernate. Teleutospores which germinate on 
Pomaceae other than species of Crataegus have apparently a 
normal mycelium, but produce pycnidia only, or aecidia with 



Fig. 220. — Cross-section through a swelling caused by Gymnosporangium. on 
Juniper-stem ; parenchyma with large cells and thin walls is present in abnormal 
quantity. (After Woernle.) 


peridia differing from those on Crataegus. My own experiments 
on the quince and mountain ash regularly produce pycnidia only. 

Wakker 3 summarizes the anatomical changes induced in 
deformed shoots of hawthorn as follows : cork, collenchyma, 
sclerenchyma, and chlorophyll are not formed, lignification of 
the cells of medullary rays no longer takes place, and there 
are few intercellular spaces. Interfascicular cambium is not 
formed, while activity of the intrafascicular cambium is suspended 
at an early period, so that the vessels remain incompletely 
developed. The epidermis is irregularly formed and liable to 
rupture. All parenchymatous cells undergo enlargement in a 
radial direction. Starch is stored up in large quantity, and 
the formation of calcium oxalate is diminished. 

1 “ On the life-history of Puccinia coronata var. himalensis,” Trans. Linnean 

Soc., London, 1891. 

2 This probably is the explanation of the long peridia obtained by Peyritsch 
.and described by Magnus ( Be.ric.hte d. naturwiss. medic. Verein, Innsbruck, 1892-93). 

3 Pringsheim’s Jahrbuch, 1892. 


388 


UREDINEAE. 


The anatomical changes induced in diseased plants of Juniperus 
communis by G. clavariaeforme were investigated by Woernle 
under my direction. His results were these: in vigorous branches, 
increased growth took place in the wood, bast, and rind; in 
weakly and poorly-grown branches, the wood increased less in 
proportion to the bast and rind. The most marked increase 
took place in the bast, and to an almost equal extent all 
round the branches. This abnormal growth absorbs so much 



Flo. 221.— Cross-section of ;i tnict of 
parenchyma in a malformed Jnniper- 
twig. (After Woernle.) 



Fm. 222. — Radial longitudinal section 
through a zone of parenchyma similar to 
Fig. 221. (After Woernle.) 


water and plastic material that higher parts of the branch 
gradually die off, and dormant buds break out on the swelling. 
Increased growth results in increase in the number of medullary 
rays, while in the tangential section their height is increased 
from 2-10 cells to 10-20 and more; the wood parenchyma is 
also more abundant, and together with t he rays frequently forms 
large masses of parenchyma in the wood (Figs. 220-223). The 
tracheae no longer follow a straight course, and numerous 
intercellular spaces appear between them ; the tracheal walls 
frequently become thickened and have an increased number of 



GYMNOSPORANGIUM. 


3S9 

fissure-like pores in place of bordered pits. The wood-elements 
in cross-section are no longer round but polygonal ; the bast 
becomes very irregular, parenchyma grows rapidly, bast fibres 
remain thin-walled and have no longer a straight course. The 
mycelium fills the bast and rind, forming masses in the inter- 
cellular spaces ; it is easiest found in the tangential section. 
On the fall of the club-shaped sporophores, a scar is left and 
under it will be found a layer 
of cork many cells thick ; when 
new sporophores are formed in 
later years, they seldom break 
through the cork layer, but 
emerge through some new por- 
tion of the bark. 

Gymnosporangium tremel- 
loides Hartig 1 on J uniperus com- 
munis. The sporocarps of this 
species occur on the branches 
and needles ; its aecidia — Roe- 
stelia pcnicillata — on leaves of 
apple ( Pyrus Malus), Pyrus Aria 
and P. Chamaemespilus. This 
Rocstelia is externally very like 
that of G. clavariaeforme on 
Crataegus. The markings on the 
cells of the peridium consist of somewhat wavy lines, not of 
short rod-like markings as in R. cornuta ; and the cells of the 
peridium are joined by a characteristic hinge-joint (Fig. 224, 
19 and 20). 

The mycelium perennates in the rind of Juniperus communis 
and J. 'nana, causing thickening of the twigs and a premature 
death of the distal portion above the swellings. The chocolate- 
brown velvety spore-cushions break out between the bark-scales 
on the swollen places, about the middle of April (Fig. 225, l). 
The teleutospores are two-celled, the earlier formed ones being 
short, ovoid, and slightly pointed at each end, while the 
later ones are thinner-walled and often more elongated 
(Fig. 225, 6-io). 

1 Hartig, Diseases of Trees , English edition, 1894. Dietel, Forstlich-natur- 
idss. Zeitschrift , 1895, p. 348. E. Fischer, Hedwiyia , 1895, p. 1. 



Fig. 223. — Tangential longitudinal sec- 
tion through the parenchyma-zone of 
Fig. 220. (After YVoernle.) 


390 


U KEDIN KAK. 


In May or June the cushions swell up and become large 
brownish-yellow gelatinous clumps, dotted over with dark points, 
the teleutospores. Promycelia arise from one or more germ- 
pores in each spore, and give off basidia with sporidia (basidio- 



Fio. 22 \.—A(cidia and Pycnidia of various spocios of Gyinnotporangium : 

G. trenullnidcn -1 and 2, accidia on leaf of Pyrin Aria ; S and 6, aocidia on leaf 
of Pyrux Mului ; l'< and 20, portions of the peridiuni of an aecidimn from f, 
showing the peculiar articulation of the cells. 

G. juniptrinum — 3 and 4, accidia on Pyrut Aucuparia ; ' and S, aocidia on 
Aintlanchirr vulgari*. 

G. clavariatfonnr—O and 10, aocidia on Py ik» I ah folia ; 11, 12. and 16, aocidia 
on tv« /«■<;«.< O.t ■iiaraalha, grown out-of-doors ; l',, the samo accidia, enlarged : 
IS, IS, and 17, aecidia on Crataegus Oxyaeanlha, indoor culture; IS, deformed 
twig of Cralacgu* bearing pycnidiu. (After Tubonf.) 


spores) capable of immediate germination. The gelatinous mass 
dries up from time to time, leaving a bright yellow scar on 
the swollen part of the host-branch. The sporidia germinate 
most easily on species of Sorbus (Pi/nis). Infections with 


GYMNOSPOEANGIUM. 


391 


Gymnosporangium juniperinum L. and G. tremelloides Hart, from 
twigs and needles of Juniperus communis produced : 


On Host-plant. 


Spore-form. 

Authority. 

Pyrus ( Sovbus ) Aucuparia, 

- 

Rostelia cornuta, 

Tubeuf. 

Aronia rotundifolia, 

- 

short aecidia, 

- ltathay. 

Pyrus Malus, - 
Pyrus ( Sorbus ) Aria, 


j-pycnidia, 

55 

Cydonia vulgaris, 

- 

Roestelia (?), - 

55 

Pyrus (Sorbus) Aucuparia , 

- 

(?) 

- Plowright. 

Pyrus Malus, - 

- 

pycnidia, 

- Thaxter. 

Amelanchier canadensis, - 

- 

Rostelia cornuta, - 

55 

Pyrus (Sorbus) Aria, 

- 

R. penicillata, 

- Hartig. 

Pyrus Malus, - 

- 

R. penicillata, 

- Nawascliin. 

Pyrus ( Sorbus ) Ckamaemespilus, 

- 

R. penicillata, 

- 

Mespilus macrocarpa, 

- 

spots, 

- Peyritsch. 

Pyrus communis, 

- 

thick spots, - 

55 

Pyrus ( Sorbus ) Aria, 

- 

pycnidia and aecidia, 

55 

Pyrus ( Sorbus ) Aria x Chamaemesp., 

thick spots, - 

55 

Pyrus Malus, - 

- 

pycnidia and aecidia, 

55 

Pyrus ( Sorbus ) Ckamaemespilus, 

- 

pycnidia only, 

55 

Pyrus ( Sorbus ) Aucuparia, 

- 

pycnidia and aecidia, 

55 

Aronia rotundifolia, 

- 

55 55 

55 

Pyrus (Sorbus) torminalis , 

- 

pycnidia and spots only, „ 

Crataegus Pyracantlia, 

- 

55 55 

55 

Cydonia vulgaris, - 

- 

55 55 

55 

Pyrus Malus, - 

- 

Rostelia penicillata, 

- Rostrup. 

Formation of pycnidial 

spermogonia always 

precedes that 

of aecidia. 




This fungus is of practical import on account of 

its occurrence 

on leaves of apple-trees. 

Its 

attacks may be 

very virulent 


and widely distributed. Eriksson mentions that near Stockholm 
it is common on apples, and so virulent that many trees have 
every leaf studded with Roestelia. (American apple-trees suffer 
from Roestelia pirata, the aecidia of Gymnosporangium macropus 
and other species. See p. 402.) 

Gymnosporangium juniperinum (L.) ( G . conicum Hedw.) 
(Britain and U.S. America). This species, also frequenting 
Juniperus communis, is distinguished by its shorter spores, 
which, as Dietel pointed out, 1 have a colourless papilla over 
each germ-pore. The teleutospores are found on both twigs 
and needles, on the former, however, they are much smaller 

1 Forstlich-naturwiss. Zeitschrift, 1895, p. 378. 


392 


UREDINEAE. 


than those of G. tremelloides. The aecidiospores — Bocstelia 
cornuta — occur on species of Pyrus (Sorbus)] they are much 
smaller than those of Roestelia penicillata. The Bocstelia 
themselves are long, curved, and horn-like, while the walls of 
the peridial cells are beset with short processes (Fig. 224). 
Where Pyrus Aucuparia occurs mixed with Pyrus Malus, 
it has been observed that Bocstelia cornuta is confined to the 
former species exclusively. The Boestelia is the cause of a 



Fio. 226 . — Qymnotporangium juniperinum and G. trtnulloide ». 7, Young spore- 

cushions breaking through the bark ; the name in swollen condition ; d, gela- 
tinous cushion arranged to show its lower surface; 4, Juniper-needle with three 
spore-cushions ; />, young Juniper plant bearing cushions on its needles ; 6 to 10, 
spores of various kinds, to show the variation in size, shape, and thickness of 
wall; 11, cell of a promycelium with a sporidium attached; 12, germinating 
sporidium. (After Tubeuf.) 

marked deformation of leaves, petioles, and even (though rarer) 
fruits of Pyrus Aucuparia and Aronia rot u ml i folia, both in 
the lowlands and mountains. 

I have produced Bocstelia cornuta on Pyrus Aucuparia by 
artificial infection with portions of spore-cusliions from twigs 
of juniper, and have observed a mountain ash in closed forest, 
with abundant Boestelia, directly beneath an overhanging juniper 
with diseased needles. 


GYMNOSPORANGIUM. 


393 


Woernle investigated tlie anatomical changes induced by the 
various Gymnosporangia frequenting the twigs and needles of 
Juniperus communis. In the needles the mycelium lives inter- 
cellularly, at first outside the endodermis, but later also penetrating 
within this. The sporogenous cushions originate on the upper 
surface of the leaf to right and left of the middle nerve, 
where the stomata occur and hypoderm is absent. At these 
places a cushion or stroma of pseudoparenchyma is produced 
and ruptures the epidermis (Fig. 226). This however is at 
once healed over by a cork-formation round the margin of the 
cushion, again to be ruptured as the latter increases in size, 
once more to be healed by cork-formation, and so on. In 



Fig. 226. — Comparison of (a) normal Juniper -needle with one ( b ) bearing teleuto- 
spores of Gymnosporangium. In a the double outline indicates the hyjDoderm ; 
the central vascular bundle and an underlying resin-canal are shown. (After 
Woernle.) 


this way a corky layer is formed under the sporogenous cushion 
and gradually displaces it. If in a following year the cushion 
be again formed, the scar is ruptured and heals as before. 
Needles frequently remain in position for two, three, or four 
years, but most of them fall off in the first autumn. Under 
the sporogenous cushion the cells of the mesophyll increase 
both in number and size. 

In considering the twig-deformations, Woernle distinguishes 
the form assumed by the Gymnosporangium on the needles, as 
just described, from a form which inhabits the thicker twigs. 
Both cause deformation of twigs, but their effects differ as follows : 
“ The needle-inhabiting form can only cause a slight swelling- 
extending almost regularly round the whole twig; the twig- 
inhabiting form, on the other hand, always gives rise to a very 


394 


UREDINEAE. 


marked swelling on one side only (Fig. 227). In the needle- 
form the swelling results from increased growth of the rind, 
with a simultaneous decrease of growth of the wood ; in the 
twig-form the growth of both wood and rind is much increased. 
With the twig-inhabiting form the medullary rays and wood- 
parenchyma increase, and at the same time become filled with 
mycelium (Fig. 228); whereas with the other form the medullary 
rays are at most only somewhat broader, and no mycelium can 
be found in the wood. The greatly swollen rind in the case 



Fio. 228.— Tangential section through diseased 
wood beneath a spore-cushion. The wood- 
elernents are much displaced bv abnormal tracts 
of parenchyma. (Only one of the latter has been 
filled in, the others left blank.) (After Woernle.) 


Fir;. 227. — Section of a nine-year twig 
of J uni per attacked by Gymnntporangium. 
The rind under the spore-cushion is 
much thickened ; the wood towards the 
same side is much broken up by tracts 
of parenchyma. (After Woernle.) 


of the twig-inhabiting form is due more to increased growth 
of the cortical cells than to increase of hast- parenchyma ; in 
the needle-form, however, the swelling is the result of increase 
of the bast, especially of the bast-parenchyma. In twigs 
infected by the needle-form, the mycelium may be found all 
round, but it has difficulty in making its way radially to the 
cambium; in the twig-form the mycelium, as early as the 
spring following infection, will he found to be in close contact 
with the cambium on the infected side, although it requires 
several years to pass round to the cambium on the opposite 
side of the twig. The mycelium and spores of the two forms 
differ little from each other.” 


GYMNOSPORANGIUM. 


395 


The strikingly characteristic cleavage of the wood by the 
overgrown elements of the medullary rays and the wood- 
parenchyma, in the case of the twig-inhabiting form, will be 
seen from the figures (Fig. 229). As already noticed, the 
sporogenous cushions are generally formed on one side. After 



Fig. 229. — Two sections from a swelling on a Juniper-branch, a. From the 
middle of the swelling ; the rind under the spore-cushion is much thickened, and 
the wood is much broken up by tracts of parenchyma, b, Section from 2 c.m. 
under a ; abnormal development of parenchyma in the wood has begun in the 
outer year-rings. (After Woemle.) 

the shedding of the cushion, a corky layer arises in the paren- 
chyma underneath it, and so a bark-scale is produced. 

Gymnosporangium sabinae (Dicks.). (Britain.) The mycel- 
ium hibernates chiefly in Junipems Sabina (Savin), and induces 
swellings on the twigs. It also occurs on Jvn. Oxycedrus} 


1 I found this host-species near Fiuiue. 


396 


UREDINEAE. 


Jan. virginiana, and Jan. phoenicea. (A reported occurrence on 
Pinus halepensis is probably an error.) 

The sporogenous cushions are little dark-brown protuberances 
which break forth in spring from swellings, or on green 



Fio. 2 SO.—Gj/mnoaporanffium tabinaf on twigs of Junij^run S nh.no, at the time 
of liberation of spores, (v. Tubeuf phot.) 

twigs and scale- leaves. These bodies absorb water, swell, and 
run together, forming transparent gelatinous masses (Figs. 230 
and 231). The teleutospores resemble those of G. juniptrinum, 
but have only four germ-pores ; they germinate on the 
gelatinous masses, and produce promycelia and sporidia. The 
latter germinate at ouce, chiefly on leaves of Pyrus co»i- 
rnunis. The pycnidia are produced on the upper epidermis 
as sticky yellow spots bearing darker dot-like pycnidia. The 
aecidia ( Rocstdia cancel lata) are found in September on the 
under-surface of the leaves of pear, also on leaf-petioles, young 
shoots, and even on the fruits. The peridia differ from both 



GYMNOSPORANGIUM. 


397 


the species already described in remaining closed at the .apex, 
the spores escaping through trellis-like slits on the lateral walls 
of the peridia (Fig. 234). 

This fungus will not germinate on apple-trees, but on pears 
every leaf may be thickly covered with aecidia and pycnidia, 
and considerable damage to the crop thereby ensue (big. 233). 



Fig. 232. — Teleutospores of G. sabinae. 
Fig. 231. — Longitudinal section through The elongated thin-walled ones are 

a conical teleutospore-sorus of Gyrano - lighter in colour than the thick -walled. 

sporangium Sabinae. (After Woernle.) (After Woernle.) 


Infections on various hosts with Gymnosporangium sabinae 
from Juniper us Sabina gave : 


On Host-plant. 

Spore-form. 

Authority. 

Pyrus communis, - - 1 

Crataegus Oxyacantha , 

(?) - 

- Plowright. 

Mespilus germanica, - 

- 

- Oersted and DeBary. 

Pyrus communis, 

Rostelia cancellata, - 

- Kathay, Tubeuf, etc. 

Pyrus communis, 

,, Micliauxii, 

\ 

1 » „ 

- Eeess. 

„ tonientosa, - - , 

Pyrus communis, 

1 

- E. Fischer. 

Pyrus communis, 

>> 

- Klebahn. 

Crataegus Oxyacantha, 


,, (uncertain).. 


398 


UREDINEAE. 


The anatomical changes exhibited in diseased parts of pear- 
leaves have been briefly described by Feutzling. 1 He found a 
radial elongation of the cells of the spongy parenchyma and an 
accompanying accumulation of starch. AVakker, about the same 
time, obtained similar results in the case of Crataegus Oxyacantha 
deformed by G. clavariueforme (see p. 387). AVakker observed 
a diminished formation of calcium oxalate ; Fentzling, however, 
found increased deposit of the same salt, not only in the form of 



Fin. 233. — Qymnotporangium tahinat in the form of Roestflia cnneellatn on 
leaves of Pear. A few twigs showing the abundance of aecidia over the whole 
tree. (v. Tubeuf phot.) 


isolated crystals but as masses. Cork- formation was suspended 
in AVakker’s case, while in Fentzling’s a partial formation of 
cork was distinguishable beneath the epidermis. The increased 
thickness of diseased leaves is due principally to multiplication 
of the spongy parenchyma, the upper layers of which frequently 
become more or less palisade-like. AVhen pycnidia (spermogoniu) 
are formed on the upper leaf-surface, the palisade parenchyma 

1 Fentzling (lor. rit.) and Peglion (Ririxta di rntoloi/in I' n/r/nlr , 1 1. ), also descr ibe 
these alterations. 


GYMNOSrORANGIUM. 


399 


of the spot in question is either completely destroyed or trans- 
formed into irregular cells, separated by intercellular spaces. 

The anatomical changes in swellings (Fig. 235) induced by 
G. sabinac on Junvperus Sabina were investigated by Woernle 
with the following results. Wood, bast, and rind are increased 
round the whole circumference of the stem. Along with 
the broadening of the year-rings, however, there occurs a 
change in the structure of the diseased wood. The same 



Fig. 234. — A few leaves enlarged from Fig. 233. The leaf to left hand bears 
pycnidia on red spots on the upper surface of the leaf ; the remaining leaves bear 
aecidia on raised portions of their surface. Several aecidia still further enlarged 
show the peridia dehiscing by longitudinal slits, (v. Tubeuf del.) 


tissues occur in the year-rings as already described for G. 
clavariaeforme, viz. thickened twisted tracheids, loosely connected 
together and with fissure-like pits ; medullary rays more 
numerous and broader ; the limits of the year-ring difficult to 
distinguish ; and a yellow pigment deposited in the walls of 
all the elements. A tissue of this nature may be found round 
the whole circumference of a twig even in the first year after 
infection, and regularly each succeeding year. Woernle only 
rarely found zones of irregular cell-formation like those 


400 


UREDINEAE. 


characteristic of G. davarmeforme. Xo mycelium occurred in 
the wood. A comparison of normal bast with that of infected 
twigs revealed changes similar to those already described for 
G. davaricuformc. In addition, it is to be noted that the 
thickened bast-fibres no longer occurred in closed masses, but 
were often completely absent in the first year after infection, 
while in all diseased twigs every intermediate stage exists 
between thin-walled bast-elements and thick-walled bast-fibres, 
such as never occur in the normal twigs ; in fact, many twigs 
had thin-walled elements only. 



Fio. 235. — Swelling from 
a branch of Juniperun 
Sabina attacked by Gpm.no- 
uporangium aabinae. Dia- 
meter at thinnest part 1'7 
centimetre, at the thickest 
6 c.m. (v. Tubeuf phot.) 


Flo. 230. Sections of a twig of Savin attacked by <•'. nibinar. 
n, At thickest part of the swelling ; 6, 3 c.m. under a and normal. 
In a is shown one of the hollow tele utospo re-cushion s ; five 
cushion-scars; in the second-year ring are two shaded rones 
of wood, chiefly composed of parenchyma. (x25.) (After 
Woemle. ) 


The sporogenous cushions of G. sabinai are formed in quite 
a different manner from those of G. davanneforim. Beneath 
each cushion the bast increases very rapidly and forms an out- 
growth, which is still further enlarged by the addition to its 
apex of six or seven rows of radially arranged cells, rounder 
and smaller than the bast-cells of the cushion. The mycelium 
penetrates between these outer cells, and forms over the whole 
cellular outgrowth a pseudoparenchyma from which the sporo- 
genous tissue arises. 


GYMNOSPORANGIUJI. 


401 


A sharply defined roundish scar of a light-yellow colour 
remains after the spores are cast. This is composed of a 
superficial layer of coloured pseudoparenchyma, with an under- 
lying scar-tissue of characteristic constitution. The latter con- 
sists of several layers of cork-cells extending from one edge of 
the scar to the other, separating the cushion from the twig- 
tissues. This scar-tissue is not broken through next year, but 
the new sporogeuous cushions break out through other parts 
of the bark (Fig. 236). 

G. confusum Plowright. 1 (Britain.) This is found on 
Juniperus Sabina along with G. sabinae, from which it is. 
difficult to distinguish. Pycnidia and aecidia are produced 
generally on Crataegus Oxyacantha and Cydonia vulgaris, rarely 
on Pyrus communis. The aecidia on Crataegus resemble those 
of C. clavariacforme on the same host, and dehisce by the 
ruptured apex of the peridium. Those produced on Pyrus 
communis are distinguished 2 from aecidia of G. sabinae on 
the same host by dehiscing through the open apex of the 
peridium. 

Infections of Gym. confusum from Juniperus communis gave 

the following results : 


On Host-plant. 
Cydonia vulgaris, 

Crataegus Oxyacantha , 
Pyrus communis, 
Crataegus Oxyacantha, 


f pycnidia and aecidia 
) tubular peridia, 


Authority. 
Wlth j E. Fischer. 


11 

11 


11 

Plowright. 


The following American species of Gymnosporangium have 
been described : 3 

On Arborvitae or white cedar : 

G. biseptatum Ellis. On twigs and needles of Cliamaecyparis 
thyoides and Libocedrus decurrens. The aecidia on Crataegus 
tomentosa and Amelanchicr canadensis. 


1 Plowright, Linnean Soc. Journal (Botany), 1887. E. Fischer, Zeitsclirift f. 
Pflanzenkrankheiten, i., 1891 ; with summary of literature. Klebahn, Forstl.- 
naturwiss. Zeitsclirift, 1 1. , 1893. 

2 E. Fischer (loc. cit.). 

:! Farlow, The Development of the Gymnosporaiujia of the United States, 1886, 
and other papers. Thaxter in various papers on Gymnosporangia, 1886 to 
1891. Halsted ( Report on Vegetable Pathology for 1888, U.S. Dept, of Agri- 
culture) gives a resume, with description and figures of G. macropus and 
treatment for orchard-rust. Fischer, Zeitsclirift f Pflanzenkrankheiten, i., 1891. 


402 


UREDINEAE. 


G. Ellisii Berk. On Chamaecypari s tliyoides. The aecidial 
stage on Pyrus Malm and P. arbutifolia. 

On red cedar ( Juniperus virginiana): 

G. macropus Lk. The aecidia and pycnidia occur on Pyrus 
Mains, P. coronaria, P. arbutifolia, Crataegus tomentosa, C. 
Douglasii, and Amelanchier canadensis ; they are known as 



Fio. 237.— Spores of 
fiym. biseptatum, (After 
Wocnile.) 



Fio. 238. — Spores of 
f#ym, R llisiL (After 
Woemlc.) 



Fio. 339. — Spores of 
<»yw. Hwcro/w*. (After 
Woernle.) 


Roestclia pirata. This is one of the commonest causes of 
apple-rust and of the deformation known as “ cedar apples ” (Fig. 
240). The anatomy of the latter structures has been described 
by Sanford. 1 

G. clavipes Cooke et Peck, occurs on Juniperus communis. 
Its aecidia and pycnidia are found on Pyrus Mains, J‘. arbuti- 
folia, and Amelanchier canadensis. 

’Sanford, AnnaU of Jiotan;/, i., 1SS7. 


GYMNOSPORANGIUM. 


403 


G. globosum Farl. Aecidia on Pyrus Malus, P. communis, 
Cydonia vulgaris, Sorbus americana, and species of Crataegus. 

G. nidus -avis Thaxt. Aecidia and pycnidia on Pyrus Malus, 
Amelanchier canadensis, and Cydonia vidgaris. On the red cedar 
it causes the “ bird’s nest ” deformation of the branch-system. 

G. speciosum Peck. On Juniperus 
occidentalis. 

G. Cunninghamianum Barcl. On 
C'Jpressus torulosa in the Himalaya. 

Aecidia on Pyrus Pashia. 

The following genera do not occur 
in Europe. Coleopuccinia, Ravenelia, 

A Iveolaria, Trichospora. 

Ravenelia alone amongst these 
contains parasitic species of import- 
ance. They all occur on Leguminosae 
and Euphorbiaceae in tbe warmer parts 
of India, Africa, and America. 1 

Ravenelia Volkensii Heim, has teleutospore-sori which appear 
on “ witches’ broom ” deformations of the twigs of an Acacia in 
Usambara. 

Rav. pymaea Lager, et Diet, produces its teleutospores on 
malformed branches of Pliyllanthus in Ecuador. 

Certain forms of Aecidium which cause deformation of species 
of Acacia should probably be included in this genus (see p. 410). 




Fig. 240 .— Cedar Apples caused 
by Gymnosporangium macropv.s. 
(v. Tubeuf del.) 


Endophyllum. 

Teleutospores originate serially on cushions which are enclosed 
in a peridium similar to aecidia ; on germination, a four-celled 
promycelium is produced. 2 Leaves of Euphorbia, Sedum, or 
S cmpcrvivum inhabited by mycelium develop abnormally. 

Endophyllum euphorbiae-silvaticae (D. C.) (Britain). Accord- 
ing to Winter, the peridia are regularly distributed over the 
underside of the leaf of Euphorbia amygdaloides ; they have 
white fissured margins either erect or somewhat turned back. 

1 Dietel, “ The Genus Ravenelia,” Hedwigia, 1894. 

2 The teleutospores of this genus might be described as aecidiospores which 
produce promycelia. 


404 


UREDINEAE. 


Spores yellow and polygonal. Leaves when attacked remain 
broad, short, and pale coloured. 

E. sempervivi (Alb. et Schw .) 1 (Britain). The aecidium-like 
patches of teleutospores occur on wild and cultivated species of 
Sedum and Elhevcria. The spores produce promycelia from 
which arise sporidia which germinate on the same host-plant. 
True aecidia are unknown, but orange-red pycnidia (spermo- 
gonia) may occur. Leaves of attacked plants are pale and 
abnormally lengthened . 2 

E. sedi (I). C.). Teleutospores occur on species of Sedum. 

The genus Pucciniosiro found in Ecuador contains few species, 
and none of them important parasites. 


Aecidium-Forms 

Tin relationships of which ore uncertain. 

Aecidium elatinum Alb. et Schw. (Britain and U.S. America). 
The witches’ broom of the silver fir . 3 This Aecidium is widely 
distributed in forests containing silver fir (Abies pedinata), 
and produces canker of the stem frequently accompanied by 
that deformation of the branch system known as a witches’ 
broom. 

In Germany it has also been observed on Abies Nordmanniana, 
A. ccphalonica, A. Pinsapo ; in North America on A. balsa m en ; 
and in Siberia on A. Pichta. 

As a result of the presence of this fungus, globose or barrel- 
shaped swellings make their appearance on stems and branches 
of all ages and on all parts of the trees. A single stem may 
carry one or many of these, and they continue to increase with 
its growth. If, as is frequently the case, the bark covering 
the swelling becomes ruptured and partially detached, then 
the wood left uncovered becomes a wound, and falls an easy 

1 Leveille, IhiUeJ. Science. Xatur., xvi., IS‘25. 

'-Illustrated in Kerner’s Xatural hinlory q/' Plante, English Edition (Fig. 358). 

3 De ltn.ry , Bolnn. Zrilung, 1S67. Weise, “ Zur Kenntniss d. Weisstannen 
krebses,” Miindener Foritl licit e Ift/tt. 1891. Heck., “ Dcr II V ixstannenkrebs." 
Springer, Berlin, 1894; with Illustrations and Bibliography. 

The canker is common throughout Britain, hut witches’ brooms have not 
been often recorded. (Edit.) 


AECIDIUM-FOKMS. 


405 

prey to wood-destroying fungi. 1 The presence of such rotting 
spots renders the tree liable to break over in their neighbour- 
hood, while they, as well as the swellings on the trunks, cause 
a considerable depreciation in the value of the timber. 

The malformations of the branch-system known as witches’ 
brooms are frequently induced by this fungus. They occur as 
a rule on the horizontal branches and form a richly branched 
bush easily distinguished, even at a distance, by a marked 



Fig. 241. — Witches Broom oj Silver Fir (winter condition). The needles, with 
spores of Aecidiv.ru clatinv.m, have fallen off, but the normal foliage remains, 
(v. Tubeuf phot.) 


negative geotropy of its twigs. The brooms not unfrequently 
start from a marked basal swelling. They may be found of all 
sizes, on young as well as old trees, on any part of the branch- 
system, and in all localities where the fir occurs (Figs. 241 
and 242). 

The aecidia of Aecidium elatinum are developed only on the 
deformed needles of the witches’ brooms. These needles are 
produced anew each spring, live only one season and are cast 

1 Polyporus Hartigii and Agaricux adipoaus in particular accompany this 
canker and bring about decay of the wood. 



406 


L'REDINEAE. 


the same autumn ; they are small, one-pointed, and pale from 
an almost complete lack of chlorophyll. In these respects they 
are quite distinct from the larger double-pointed normal needles 
with their dark-green colour and a period of growth extending 
over several years. All the needles on a broom are as a 
rule stunted in the manner described, yet single branches 
may be found with needles quite normal ; such contain no 
mycelium, or, if so, it has found its way in too late to have 
any effect on their growth. 



Fin. 242.— H’itche * Broom oj Silver Fir (summer condition). The markedly 
negative geotropic broom has its origin in a distinct basal swelling, (v. Tul»euf 
phot.) 


The various tissues of the witches’ brooms also undergo 
considerable modification as compared with normal twigs. A 
thicker and softer bark is present, due to the parenchymatous 
cells of both outer rind and bast having enlarged in size and 
increased in number; the cork layers are also abnormally in- 
creased. The same changes may be observed in the rind of the 
swellings, and to this their increased size must be chiefly ascribed. 
The wood both in twigs and swellings is much increased ; 
the year-rings however are very variable, sometimes they arc 1 
broader than the normal, again they may be diminished or 
even altogether wanting; where however the wood decreases, 
there the bast increases in proportion. This lack of uniformity 



AECIDIUM-FORMS. 


407 


on the 


in the growth of the wood disturbs the elements, so that 
they are irregularly developed and more or less twisted . 1 

A mycelium inhabits the tissues of abnormal twigs and 
cankered swellings. It grows in the intercellular spaces of 
the rind, between the bast cells and outer parts of the wood, 
and derives nutriment by means of haustoria ; these either bore 
through the cell-walls, or only press closely against them so 
as to cause depressions. 

Spore-formation takes place on the needles of the witches’ 
brooms. The pycnidia (spermogonia) are produced 
upper side beneath the cuticle 
and emerge through it as little 
yellow points. The conidia (sper- 
matia) are tiny globose colourless 
bodies. The aecidia come later 
during June and July in irregular 
rows on the under side of the 
leaf. Their peridia break out as 
low dome-like structures, the 
apices of which rupture irregu- 
larly to allow escape of aecidio- 
spores. In spite of numerous 
infections, I)e Bary was unable 
to observe the penetration of a 
germ-tube into needles or twigs 
of silver fir. Weise believes that 
infection of the fir takes place 
on twigs which have just emerged 
from the bud. 

As a preventive measure, all 
witches’ brooms should be cut off 
before spore-formation begins, and 

stemswith canker-wounds should be removed during forest-thinning. 
For further details the monograph of Heck may be consulted. 

Aecidium strobilinum (Alb. et Schw .) 2 (Britain). Spruce- 



Fio. 243. 


-Aecidivm strobilinum on a Spruce- 
cone. (v. Tubeuf phot.) 


1 Note. — Further details of the anatomical changes induced in the tissues of 
these witches’ brooms may be obtained in the German edition of this work 
(pp. 420-421), or in the original thesis by Hartmann, (Anatom. Vcrgleichung d. 
Hexenbesen der Weisstanne. Inaugural Dissertation, 1892.) (Edit.) 

2 Reess, Rostpil-.formen d. Coniferen., 1869. Oerstedt, Xaturh. for Vidensk. 
Medd., 1863, i. 


408 


UREDINEAE. 


cone rust. This disease is found on the cones of spruce. 
The aecidia are brown somewhat flattened spheres, and appear 
in large numbers on cones distinguished by their scales standing 
stiffly open even in damp weather (Fig. 243). The germ- 
tubes of the fungus find entrance in spring into the flowers 
or young spruce-cones, and the mycelium lives parasitic in 
the green scales without causing any marked change in 
their growth, although the ovules are more or less injured. 
Xo mycelium has ever been found in the lower cone-axis, nor 
in the shoots, so that the disease must be the result .of in- 
fection by spores only. 



Fto. 244. — A'ddium *t robilinuhi. 1, Conc-scalc of Spruce with aecidia, those to 
left dehiscing their yellow spores, those to right still closed, (v. Tul>cuf del.) 
2, Section through an immature aecidium. 3, Part of 2 enlarged />« >*, peridium ; 
«p. spores; zi r, intermediate cells; *pir 9 sporophores ; in, mycelium; jxir, the 
scale-parenchyma. (After Hecss.) 


The aecidia break out on the inner (rarely the outer) side 
of the bases of the cone-scales ; each is enclosed in a firm 
brown lignified peridium, which ruptures by a cross-fissure 
and becomes an open disc. The young spores are joined by 
small intermediate cells, which arc gradually absorbed to 
form a layer of gelatinous lamellae on the spore-coats 
(Fig. 244). 

Teleutospores of this Aecidium are unknown. 


AECIDIUM-FORMS. 


409 


Aecidium pseudocolumnare Kuhn. 1 Occurs on needles of 
Abies pcctinata in Germany ; in Britain, however, on this and 
several other species of Abies. It is distinguished by its large 
white spores from the Arc. columncire of Calyptospora (p. 372). 

Aec. Magelhaenicum Berk. This species occurs on various 
species of barberry. The mycelium hibernates in the shoot- 
buds and causes them to develop as witches’ brooms, bearing 
on the lower surface of their leaves aecidia with long, white, 
sac-like peridia. The allied teleutospore-form is as yet unknown. 

Aec. clematidis D. C. (Britain and U.S. America). On Clematis Vitalba, 
C. recta , and other species. It is related to Puccinia agropyri Ell. et Ev. 2 

Aec. Englerianum Henn. et Lind. 3 produces a peculiar antlerdike 
branching of the twigs and leaves of a Clematis at Eritrea (Lytri) in the 
Grecian Archipelago. 

Aec. punctatum Pers. (Aec. quadrifidum D.C.) (Britain and U.S. America). 
This is a common species on Anemone (Fig. 190) and Eranthis. The 
aecidia have white peridia, which on dehiscence break into four lobes. 

Aec. leucospermum I). C. (Britain and U. S. America). On Anemone 
nemorosa (Fig. 190). 

Aec. hepaticae Beck. On Anemone Hepatica. 

Aec. ranunculacearum D. C. (Britain and U.S. America). On species 
of Ranunculus. A collective name for aecidia of several species of Uromyces 
(p. 336), and Puccinia (p. 349). 

Aec. aquilegiae Pers. (Britain and U.S. America). On Aquilegia 
vulgaris and other species. (See Puccinia agrostidis , p. 349.) 

Aec. actaeae (Opiz.). On leaves of Actaea spicata in Europe and America. 

Aec. barbareae D. C. On species of Barbarea (Britain). (See Pucc. 
fcstucae, p. 349.) 

Aec. circaeae Ces. On species of Circaea. 

Aec. grossulariae Sehum. (Britain and U.S. America). On Ribes Grossu- 
laria and R. rubrum. Klebahn believes it is related to a Puccinia on Care.v. 

Aec. bunii D. C. On Conopodium denudatum in Britain. (See Pucc. 
bistortae, p. 355.) 

Aec. periclymeni Schum. On species of Lonicera. (Britain.) (See Pucc. 
festucae, p. 349.) 

Aec. compositarum. A provisional species-name for a large number of 
aecidia frequenting Compositae, and by no means resembling each other. 

Aec. leucanthemi D. C. A European species with its Puccinia- form on 
Carex montana. 

Aec. cyani D. C. On Centaurea Cyanus. 

Aec. ligustri Strauss. On Privet. 

1 Hedwigia, 1884. 

2 Dietel, Oesterreicb botan. Zeitung, 1892. 

:1 Engler's Botan. Jahrbuch, 1893. 


410 


UREDINEAE. 


Aec. phillyreae D. C. On species of Phillyrea (Britain ?). 

Aec. fraxini Schwein. This causes serious ilamage in America to the 
foliage of Fraxinus viridis and Fr. americana . 1 It lias also appeared in 
Europe on the latter species introduced from America. 

Aec. nymphaeoidis I). C. On leaves of Limnanthemum, Nuphar , and 
Xymphaea. (Britain.) 

Aec. pedicularis Eili. On Pedicidciris. (Britain.) (See Pucc. paludosa, 
p. 351.) 

Aec. prunellae Wint. On Prunella vulgaris. (Britain.) 

Aec. euphorbiae Gmel. is found on many species of Euphorbia. It is 
probably the Aeridium-iovin of Uromyces pisi. (Britain and'U.S. America.) 

Aec. convallariae Sclium. (Britain and U.S. America). Probably a 
provisional species-name for aecidial forms found on Conrallaria, Polygon - 
atum, Paris , Lilium, etc. (See under Puccinia.) 

Aec. ari Desm. (Aec. dracontii Schwein.) is found on species of A mm. 
(Britain and U.S. America.) (See Pucc. phalaridis, p. 34!).) 


The following species are found on Acacia and seem to have 
strong affinity with the genus Ravenalia : 

Aec. esculentum Barcl. produces deformation of twigs of Acacia eburnca 
in India. Twigs of this kind, likewise shoots deformed by Aec. urtieae var. 
himalayense Barcl., and pine-shoots deformed by certain species of Perider- 
mium, are eaten in various parts of the world. 

Aec. acaciae (Henn.) on Acacia ctbaica in Abyssinia. This is said by 
Magnus to cause witches’ broom deformation. 

Aec. Schweinfurthii Henn. causes malformation of fruits of Acacia 
Fistula in Africa. 

Aec. ornamentale Kalcli. causes curvature of shoots of A' icia horrid a 
at the Cape. 


The following are some of the more important species 
recorded for North America only : 

Aecidium dicentrae TreL Leaves of Dicentra and Corydalis 
Aec. monoicum Peck. Leaves of Arahis. 

Aec. drabae Tr. et Gall. 

Aec. lepidii Tr. et Gall. 

Aec. proserpinacae B. et ( '. 

Aec. Mariae-Wilsoni Peck. c ... , 

( )n species of I iota. 

Aec. Petersii B. et C. ‘ 

Aec. cerastii Wint. 

Aec. pteleae B. et C. On leaves of Ptelea trifoliata. 

Aec. xanthoxyli Peck. 

Aec. splendens Wint. In the cotyledons of Croton mouanthogyn ■ ' 

Aec. aesculi Ell. et Kell. 

Aec. psoraleae Peck, and Aec. onobrychidis Burr. On species of Psoralea 
1 Bound, American Xa turalixt, 1SSS. 


AECIDIUM-FORM.S. 


411 


Aec. Peckii De Toni and Aec. oenotherae Mont. On leaves of species 
of Oenothera. 

Aec. sambuci Schwein. On leaves and stems of Sambv.cv.s. 

Aec. ceanothi Ell. et Kell. 

Aec. abundans Peck. On species of Symphoricarpus. 

Aec. cephalanthi Seym. On Cephalantkus occidentale. 

Aec. erigeronatum Schwein. On many species of Erigeron. 

Aec. asterum Schwein. On species of Aster and Solidago. 

Aec. polemonii Peck. On Polemonium and Phlox. 

Aec. apocyni Schwein. On leaves of Apocynum. 

Aec. Jamesianum Peek, and Aec. Brandegei Peck. On leaves of species 
of Asclepias. 

Aec. myosotidis Burr. On leaves of Myosotis vena, etc. 

Aec. plantaginis C'es. On leaves of species of Plantago in Europe and 

America. 

Aec. pentastemonis Schwein. On species of Pentstemon. 

Aec. giliae Peck. 

Aec. lycopi Gerard. On leaves and steins of Lycopvs europaev.s. 

Aec. iridis Gerard. 

Aec. macrosporum Peck, and Aec. smilacis Schwein. On species of 
Smila.r. 


Peridermium. 

Peridermium pini (Willd.) 1 is found on pine-trees in Europe, 
Britain, and United States. A teleutospore-stage of this has not 
as yet been identified, although a very similar species ( Peri - 
dermium Cornui Rostr. et Kleb.), also occurring on the bark of 
pines, has been proved to have as its teleutospore-fonn Cronartium 
asclepiadeum. 2 

The mycelium of Peridermium pini lives intercellularly in 
the rind, bast, and wood of Pinus sylvestris, P. Laricio, P. 
halepensis, P. maritima, and P. montana. It lives and extends 
through the stem for years, attacking the living cells and 
absorbing nutriment from them by little haustoria. The cells 
of parenchymatous tissues are those most generally attacked, 
and the mycelium has been found to penetrate along the 
medullary rays to a depth of 10 c.m. into the wood-mass. ' 
The cells of attacked parts lose their normal content including 
starch, and secrete crude turpentine in such quantity as to 
completely permeate their walls, and even to form drops. In 
this way portions of the wood become completely saturated 

1 R. Hartig, Wichtige Krankheiten d. Waldbaumem. 

2 Klebahn, Berichte d. deutsch. botan. Gesellschaft, 1890. 


412 


UREDINEAE. 


with resin, and as the same process goes on in bast and rind, 
the turpentine overflows from fissures or wounds in the bark. 
During the summer the mycelium grows amongst the dividing 
cambium-cells and kills them. Where this occurs the' year- 




Fio. *246. — Pi -fidt t'inium pint (<ortiroln\ 
Young twig Waring numerous aecidia. 
(v. Tubcuf pilot.) 


Fio. *245. — P> ridcrmium pint (rorii<^lfi\ 

Brunch and lateral twig* distinctly 
swollen where attacked. They also War 
aecidia. (v. Tubeuf phot.) 


ring ceases to thicken, but as the mycelium seldom 
during the first year in killing the cambium all 


succeeds 
round a 


PERIDERMIUAL 


413 


branch, the living portions of the ring grow on with increased 
vigour, and even attempt to close over the injured portion. 
This irregular growth, continued in many cases for years, pro- 
duces abnormal cross-sections (Fig. 248). The mycelium 
grows out centrifugally from diseased spots, so that the wounds 
continue to enlarge, and the disease becomes easily noticeable 
on account of the deep channels and distorted swellings on 
the pine branches and stems. As the disease spreads inwards 
into the stems, the conduction of water is interfered with and 
the branches above such wounds dry up and die off. Whereas 



Fig. 247. — P (rider mi v/m pini ( corticola ). a, a, Mycelial stroma developed in the 
rind ; the host-cells have become isolated from each other and contain 
haustoria, h, of the fungus, b, Basidia composed of much smaller cells than in 
the needle-inhabiting aecidia. p, The peridium. (After R. Hartig.) 

young plants soon succumb to attack, the struggle with old 
trees may go on for years. Fresh infection of older stems 
occurs generally in the higher parts of the tree, where the 
bark is still thin. 

Pycnidia (spermogonia) are developed between the rind- 
parenchyma (periderm) and cork, generally towards the margin 
of diseased spots. The conidia emerge from the ruptured 
cork-layers of the bark as a honey-sweet liquid. H. Mayr 
states that this liquid is given off in such quantity from 
species of Peridermium in Japan, that it is collected and 
eaten by the natives. 


414 


UREDINEAE. 


The aecidia appear in June as wrinkled yellow sacs 
emerging from the bark of swellings. They continue to develop 
in succession for years on the living parts of attacked 
branches, but according to Hartig they cease to make their 
appearance on old stems, even when a mycelium is present. 
This disease is the cause of great damage to pines, especially 
where planted as pure forest. One case is recorded 1 of a 
forest near Kohlfurt where 90 per cent, of the trees in an 
old plantation were “ stag-headed ” on account of a deficient 



Fin. *248. -Peridtrmiv.ru pin!. Section through a diseased stem of Pine showing the 
gradual killing of the cambium by the fungus, (v. Tuheuf phot.) 

supply of water in the crown accompanying attacks of this 
fungus. Until more is known of its life-history, preventive 
measures cannot be well extended beyond cutting down 
infected trees. 

.'iiThe following species of Peridrrmium have been observed 
on species of Pinus : 

A. On the needles: 

Peridermium oblongisporium Puck, (mow Cofensporiutn on 

Pinus syloestris and P. austriaca (p. .474). 

P Klebahni, P. Soraueri, P. Stahlii, P. Plowrightii, and P. Fischeri. 

On Pinus sylvestris ; related to various species of Coleosporiuni. 

P. piriforme Peck. On Pinus speciosa in 0.8. America. 

P cerebrum Peck. On Pinus ri<jida in North America, 


1 .Marker at Sclilesien. Forstverein, 1893. 



PERIDERMIUM. 


415 


P. filamentosum Peck. On Pinus ponderosa, also in America. 

P. Harknessii .Moore. On Pinus ponderosa , P. insignis , P. Sabineana, 
and P. contorta in California. 



Fig. 249 . — Peridermium giganteum on Pinus Thunbergii from Japan, (v. Tubeuf 
phot. — the specimen presented by Prof. Grasmann of Tokio.) 


P. brevius Barcl. On Pinus excelsa in India. 

P. complanatum Barcl. On Pinus longifolia in India; on rind as well 
as needles. 


B. On the rind or bark : 


Peridermium Cornui Rostr. 
et Kleb. (now Cronartium 
asclepiadeum, p. 381). On 
Pinus sylvestris. 

P. strobi Kleb. (now Cro- 
nartium ribicola , p. 382). On 
Pinus Strobus, P. Lambertiana , 
(and P. Cembra). 

P. pini( Willd.). On Pinus 
sylvestris. (Britain and U.S. 
America.) 

P. orientale Cooke. On 
Pinus rigida and P. virgini- 
ana in America ; also P. 
longifolia in India. 




Fig. 250 . — Peridermium giganteum on Pinus densiflora 
from Japan, (v. Tubeuf phot.) 



416 


UREDINEAE. 


P. Ravenelii Tliiini. On Pinus australis in North America (probably 
a variety of P. oblong isporium). 

P. deformans Mavr. On Pinus mitis in America. 

P. giganteum (Mayr). On Pinus densi flora and /'. Thunbergii in Japan. 
This causes very conspicuous deformation of its host (Figs. 249 and 250). 
P. complanatum Hard. On Pinus longifolia in India. 

The following species frequent other hosts : 

Peridermium conorum Thiim. 1 This aecidium first found by 
I)e Bury in Thuringia, has recently been imported in Denmark, 


Iiussia, and America ; also in 
Upper Bavaria by v. Tubeuf 



in September, 1895. It takes 
the form of two large aecidia, 
which make their appearance 
on the outer or inner side of 
the cone-scales of spruce. The 
white peridia break through 
the epidermal tissues which 
then remain as a brownish 
sheath around each ruptured 
peridium (Fig. 251). The 
spores are separated by inter- 
mediate cells, and their outer 
coats are studded with poly- 
gonal warts. The cone-scales 
bearing aecidia contain a very 
large quantity of starch. Tel- 
eutospores of the species are 
unknown. 

Peridermium coruscans 

Fries. 2 The mycelium of this 


fungus seems to perennate in 
twigs and buds of spruce. Twigs unfold from the bud as 
deformed, shortened, cone-like shoots bearing very short broad 
needles of a pale colour. The aecidia are produced on the 
deformed needles as broad lineal cushions with white peridia. 
They originate under the epidermis which they rupture, and 
break out on one side of the needle. 


1 Reess, fiostpibjbrnn u, 1869. 

2 Roetrup, Vidtnsk. tlehk. Forhand/., ISS4. 


PERIDERMIUM. 


417 


The soft hypertrophied shoots are eaten. They occur chiefly 
in Scandinavia, but recently were observed by Gobi and Tranzschel 
in the neighbourhood of St. Petersburg . 1 

O o 



Fig. 252. — Aecidium coruscans on malformed shoots of Spruce. The compact 
abnormal shoots thickly covered with white aecidia contrast strongly with the 
normal portions, (v. Tubeuf phot, from material presented by Prof. Fries, 
Upsala.) 


P. Engelmanni Thiim. On cones of Picea Smithiana. (U. S. 
America.) 

P. piceae Barcl. On needles of Picea Smithiana. 

P. Peckii Thiim. On needles of Tsuga canadensis (U.S. America). 

P. balsameum Peck. On needles of Abies balsamea (U.S. America). 

P. ephedrae Cooke. On Ephedra in U.S. America. 

P. cedri Barcl. On needles of Cedrus Deodara in India. 

P. Balansae Corn. On leaves of Dammara ovata in New Caledonia. 

'Also reported at Haslemere (Britain), Grevillea, xix., 1890. 

2 D 


418 


UREDINEAE. 


1 


Caeoma. 

Caeoma abietis-pectinatae Reess . 1 Tlie aecidiospores may 
be found on the lower surface of young 
needles of silver fir ; the aecidia are yellow 
elongated cushions situated on either side 
of the needle mid-rib, and are without 
peridia. Pycnidia (spermogonia) are pro- 
duced before the aecidia. The mycelium is 
septate and intercellular with few haustoria. 
I have found the fungus fairly abundant 
on the Alps and in the Danube valley near 
Passau. Teleutospores are unknown. 

Caeoma deformans (Berk, et Br.) Tubeuf 
( Uromyces deformans Berk, et Br . 2 or Caeoma Asanuro Shirai ). 3 
This induces the formation of “ witches’ brooms ” or of antler-like 


1 

P 

f 


Fig. 253. Caeoma abieli* 
pectinatae. Needle of Silver 
Fir showing Ca^oma-patches 
on the lower surface, (v. 
Tubeuf del.) 



Fio. 254 . — Caeoma drjonnan * on Thuiopni .< dotabrata. (v. Tubeuf phot, from dried 
material presented by Prof. Grasmann of Tokio.) 


'Reess, RostpUzfonnen, IS69. 

-Berkeley, “The fungi collected during the expedition of H.M.S. 
longer.”' Jour, of Linnean Soc., xvi., 187(5. 

'•Shirai, Botanical Magazine, Tokio, 1S89. 


‘Chal- 


CAEOMA. 


419 



leafless shoots on Thujopsis dolabrata in Japan, whence they were 
sent to me (Figs. 254 and 255). One example (not figured) was 
as large as a young child’s head. 

The shoots of the witches’ brooms are furnished with vascular 
bundles and possess a parenchyma rich in starch-content. 
Each branch of the deformed shoot termi- 
nates in a hemispherical saucer-shaped 
meoma-cushion, at first covered over by 
the epidermis, but with no peridium. The 
caeomrt-discs are at first brown, but after 
the epidermis bursts and rolls back, the 
yellow dusty spores appear. The spores 
arise serially from very short basidia ; they 
are yellow and have striped membranes. 

The witches’ brooms also exhibit marked 
hypertrophy (Fig. 254). In the supporting branch both wood 
and bark are considerably increased. Large medullary rays occur 
in the wood, and nests of thin-walled parenchyma are interpolated 
between the regular tracts of tracheae, so that the general 
arrangement resembles that shown in juniper by Wornle’s 
researches on G-yrnnosporangium. The parenchymatous groups 
of cells in the wood appear to the naked eye as brown spots. 
They are permeated by a vigorous intercellular mycelium, which 
sends off large haustoria into the adjacent cells. 


Fig. 

mans. 

ceding 


255. — Co.eoma defor - 
Portion of the pre- 
figure enlarged to 
show the Caetma-discs on the 
ends of twigs, (v. Tubeuf 
del.) 


Caeoma laricis (Western !). 1 On needles of Larix . (Britain.) 

C. orchidis A. et S. On orchids. (Britain.) 

C. chelidonii Magn. On Chelidonium majus (U.S. America). 

C. fumariae Lk. On Corydalis. 

C. euonymi (Gmel.). On Euonymus europaeus (Britain). 

C. confluens (Pers.). On Ribes alpinum, R. rubrum, etc. 

C. nitens ( C luminatum ) is the well-known Blackberry-rust so common 
in the United States. It is probably a form of Puccmia Peckiana . 2 

C. aegopodii (Rebent.). On Aegopodium Podagraria and Chaerophyllum 
(iromaticum. 

C. ligustri (Rabh.). On Ligustrum vulgare. 

C. ari-italici (Duby). On Arum maculatum. 

C. alliorum Link. On AUium ursinum, A. oleraceum, etc . 3 
C. saxifragae Strauss. On Saxifraga granulata . 3 
C. mercurialis (Mart). On Mercurialis perennis . 3 


1 This and most of the other species are only stages of some Melampsora. 

2 Clinton, Botanical Gazette, 1895, p. 116. 

3 These three species are given as British in Plowright’s ‘Uredineae.’ (Edit.) 


420 


UREDINEAE. 


Uredo-Forms of uncertain relationship. 

Uredo agrimoniae (D. C.). On species of Agrimonia (Britain and U.S. 
America). Dietel regards it as related to Mdampsora (Theco/jfora) agri- 
moniae. 

U. Muelleri Sehroet. On J tabus fruticosus (Britain). 

U. symphyti D. C. On Symphytum officinale (Britain). 

U. phillyreae Cooke. On Phillyrea media (Britain). 

U. macrosora De Toni. On Epilobivm tetragonum (U.S. America). 

U. vitis Thiim. This species first attracted notice as a disease- 
producing fungus in Jamaica in 1870, but it had been found previously 
in the United States. It causes spots on the upper surface of leaves. 1 

U. fici Cact. On Ficus Carica in Italy and U.S. America. 

U. quercus ( Brond.). On species of (piercus (Britain and U.S. America). 

U. iridis. On many species of Iris (Britain). 

U. glumarum Rob. On Zen Mais in Belgium and England. 

U. sorghi Fuck. On Sorghum halepense in Greece; (compare with 
Urorayces and Puccimia on the same host.) 

U. gossypii Lager.- This has been observed in South America causing 
a rust on cotton-plants and injuring the yield of cotton. It appears as 
small purple-brown spots ; the spores are oval and yellow. 

Uredinopsis.* 

[This is a new genus found by Magnus to contain several 
Uredineae parasitic on Ferns . 4 The aecidial stage is unknown. 
The uredospores are abjointed singly from the ends of sporo- 
genous hyphae ; they are unicellular and without germ-pores. 
The uredospore-sori are enclosed in a pseudoperidium of elon- 
gated tubular cells. Unicellular teleutospores (?) are given 
off from sori similarly to the uredospores. Pluricellular teleuto- 
spores are developed from the mycelium in the intercellular spaces 
of the host-plant, never from crust-like sori. On germination 
four-celled promycelia with spherical sporidia are produced. 

Uredinopsis filicina (Niessl.) Magn. On lower surface of fronds of 
Phegopteris (Polypodium) vulgaris, causing death. 

Ur. struthiopteridis Stoermer. On sterile fronds of Struthioptcris 
germanica. 

Ur. pteridis Diet, et Holw. On /‘ten's aquilina :.] (Edit.) 

1 Massee ( (Ireri/lea xxr., p. 11!)) states this species to be identical with (J. 
Vialae of Lagerheiin (Revue yen. <l> Botaniqw , 1890). 

- Lagerheim, Journal of Mycology, vu. p. 4.S. 

■' Dietel, “ Uredo polypodii ( I’ers. ) ” Oestemich. botan. Zeilsvhrift, 1894; also 
“ I)er Battling Uredinopsis,” Ber. d. deutsrh. botan. Oes., 1895, p. 320. 

4 These host-plants do not come strictly within the scope of this work, but 
a short note on the genus is necessary. (Edit.) 


BASIDIOMYCETES. 


421 


BASIDIOMYCETES. 

The sporophores, known as basidia, are structures with a 
definite shape, and with lateral branches, the sterigmata, from 
which a definite number of exospores — basidiospores — are ab- 
jointed, the basidia then becoming functionless. Basidia and 
basidiospores are characteristic of all Basidiomycetes, conidia 
and chlamydospores being produced only exceptionally. 

The basidia generally arise from an extended layer — -the 
hymenium — which in the higher genera forms part of a con- 
spicuous complex sporophore. The basidia do not therefore 
originate from the germination of a spore, as do the promycelia 
of the Uredineae and Ustilagineae, but from special sporophores 
(rarely from the mycelium itself), whose surface they occupy, 
or in which they are enclosed. 

In the course of development, two nuclei have been found 
to copulate in the basidial cells. Thereafter they divide and 
produce four (rarely two) new nuclei (Autobasidiomycetes), or 
after the division of nuclei, cross-septa are formed, thus making 
the basidia pluricellular (Protobasidiomycetes). In both cases 
the nucleus passes through the sterigmata into the developing 
basidiospores, and on the germination of these spores, it divides 
into two nuclei, the starting points for further nuclear division. 

As just indicated two divisions of the group may be dis- 
tinguished : (1) Protobasidiomycetes, (2) Autobasidiomycetes. 

Protobasidiomycetes. 

Under this class are included the Auricidarieae, Pilacrcae, and 
Tremcllinae, the first two possessing basidia divided, as a rule, 
by cross-septa into four cells, the last with basidia also divided 
into four cells, which are formed, however, by two longitudinal 
walls set at right angles to each other. A sterigma grows out 
from each cell and produces a single spore, after which the 
basidium dies away. The basidia of the Pilacreae are produced 
inside closed sporocarps (angiocarpous), those of the other two 
groups are exposed (gymnocarpous). Pai’asites are unknown 
amongst the Protobasidiomycetes. 

Autobasidiomycetes. 

Basidia unicellular (autobasidia), the sterigmata formed on 
the apex of the basidium, and each giving off a single basidio- 


422 


BASIDIOMYCETES. 


spore. The basidia originate from basidial layers or from complex 
hymenia, produced either inside some special structure, or on 
the surface of special sporophores, or on some definite part 
of these. 

The group may be sub-divided into the Dacryomycetes, Hymeno- 
mycetes, and Gasteromycetes (including Phalloideae). Of these only 
the Hymenomycetes contain species parasitic on plants, the others 
include harmless saprophytes, which live in the soil, some of 
them, however, taking part in the formation of mycorhiza. 


THE HYMENOMYCETES. 

The unicellular basidia give off from their apices four (any 
number from 2 to G may occur) sterigmata, from each of 
which a single basidiospore is abjointed. The basidia arise 
from free exposed hymenia, which generally occupy the whole 
or part of large compound sporophores. The greatest develop- 
ment of the sporophore is attained in the umbrellas of the 
Ayaricineae, and the large discs of the Polyporcae. It is only 
amongst the lowest genera, like Exobasidhnn, that the basidial 
layers are produced directly on the organs of the host, and the 
basidia arise directly from the liyphae. 

Reproductive cells, other than basidiospores, are rare. In a 
few cases amongst the Polyporcae, llrefeld and others have 
observed conidia and chlamydospores ( Oidia , etc.) ; while some 
few Ayaricineae have the latter form of spore, but never conidia. 

The mycelium is of a very varied nature. It frequently 
inhabits wood, and in many different ways brings about 
destruction of lignified tissues. Other modifications are seen 
in the forms of mycelium known as rhizomorphs, rhizoctonin, 
mycorhiza, and other closely felted masses of various shapes, 
which will be considered in detail as occasion requires. The 
formation of clamp-connections is also a special feature of the 
mycelium of the Hymenomycetes. In many cases the mycelium 
retains its vitality and perennates for several years. 

The genus Ecobasid i uni consists of parasites which produce 
malformation of their host ; many of the Polyporcae and 
Ayaricineae are deadly enemies of forest and fruit-garden, 
while as wound- parasites many of them are specially dangerous. 
The general means of combating them consist in cutting out 


HYMEN OMYOETES. 


423 


any sporophores and applying tar to the wound, while diseased 
stems in the forest should be felled. Immediate artificial 
closure of wounds in the wood is a very effective preventive 

measure. 1 

The Hymenoinvcetes are divided into Tomcntellede, Exobasi- 
diaceae, Hypochnacccie (included by Brefeld in the Tomentelleae), 
Thclephoreae, Clavarieae, Hydneae, Po/yporeae, and Agaricineae. 
All contain parasitic species. 

EXOBASIDIACEAE. 

Exobasidium. 

The basidia are formed on the extremities of branches of 
the mycelium, which break out through the cuticle of attacked 
organs. The mycelium lives inside the host-plant, and induces 
considerable malformation. The basidia emerge on the surface 
of the host (similarly to the asci of the Exoasci ), and from 
each of the four sterigmata a single spore is given off. 

Exobasidium vaccinii Wor. 2 (Britain and U.S. America). 
This is the cause of a very common and conspicuous deformation 
which affects the leaves, flowers, and shoots of Vaccinium Vitis- 
Idaea (Fig. 256). Leaves, where affected, become thickened 
and form irregular blisters vaulted towards the lower surface 
of the leaf, so that the lower epidermis covers the convex 
side and the upper epidermis lines the concavity. Chlorophyll 
is absent in the swollen tissues, but where blisters are exposed 
to direct light a bright red cell-sap is developed. Parts of 
the leaf adjoining diseased spots may remain normal and 
green. Flowers or their parts undergo similar malformation ; 
twigs become more or less thickened and twisted, their chloro- 
phyll disappears, and a reddish cell-sap is produced. On such 
diseased places spores are produced during the summer, after 
which the poorly developed tissues dry up and wither. 

When this fungus is present in the young tissues of its 
hosts, it exerts a very marked influence on their development. 
The palisade cells of the leaf become enlarged, while their 
chlorophyll almost wholly disappears, and is replaced by a red 

further details on this point have already been given, General part, p. 72. 

-Woronin, Verhancl. d. naturfor. Ges., Freiburg, 1S67 ; with 3 plates, 
Brefeld, Schimmelpilze, vin., 18S9. Wakker, Pringsheim’s Jahrbuch, 1892. 


424 


BASIDIOMYCETES. 



cell-sap. Cells of the parenchyma in flower and stem enlarge to a 
still greater degree. Intercellular spaces are as a rule obliterated, 
but when present are filled with a fine mycelium. Wakker gives 
us further results of the fungoid attack ; crystal-glands, normally 
numerous, are no longer formed, but are replaced to some extent 
by indistinctly defined crystals of calcium oxalate. Transitory 
starch is stored up in large quantity. The fibro-vascular bundles 


Fio. ‘IW.- B.roljatidium vaccinii inducing outgrowths on leaves of Eaccimuttl 
Vitit-Idata. (v. Tubcuf phot.) 

present a striking modification, the primary xylem alone is 
normal, the vessels of the secondary wood remaining rudimentary; 
other parts are not lignified, and the phloem is only indistinctly 
laid down. 

A mycelium is present in all deformed parts, but absent in 
normal green tissue. It becomes massed to form a hyraeninl 
layer beneath the epidermal cells or between their outer walls and 
the cuticle. The steriginata do not exceed four in number, and 



EXOBASIDIUM. 


425 



from each a spindle-shaped spore is abjointed (iig- the 

basidiospores divide in water by formation of cross-septa, and 
a germ-tube arises from each terminal cell. On a young leaf 
of Vaccinium the germ-tube 
penetrates and gives rise to 
a mycelium (Fig. 258): on 
other substrata the germ-tube 
sprouts into several very fine 
sterigmata, from the extremi- 
ties of which a series of conidia 
are abjointed ; the conidia 
may give off secondary coni- 
dia, perhaps also tertiary. In 
nutritive solution, Brefeld ob- 
tained an increased number of 
germ-tubes and a continuous 
production of conidia ; in air, 
conidia were produced on conidia, but inside the solution the 
conidia gave off hyphae from which new conidia arose. 


Fig. 257 .—Exobasidiurn vaccinii. The basidial 
layer is shown developing from the intercellular 
mycelium of the shoots. (After Woronin.) 



Fig 258 — Exobasidiurn vaccinii , Germinating basidiospores. The septate spores 
have iriven off germ-tubes which penetrate into the cowberry leaves, either by 
stomata or through the epidermis. The lowest spore is forming conidia. (After 
Woronin.) 

This Exobasidiurn is very common on the cowberry ( Vaccinium 
Vitis-Idaea )} It occurs less frequently on the bilberry ( Vac - 

1 Several American Ericaceae are given as host-plants in the “Host-Index. 


426 


BASIDIOMYCETES. 


cinium Myrtillus ) 1 causing a premature fall of the leaf and 
suppression of the flower. The external symptoms of the disease 
differ somewhat from those on cowberry. Diseased leaves are 
much larger than the normal, but are neither thickened nor 
blistered ; on the under side they have a whitish or reddish 
coating, and fall off easily. I have never observed the disease 
on the stems of bilberry. In spite of these external differences, 
it is believed that the host-plants are in both cases attacked by 
the same species of Exobasidivm, but I do not know of any 
observations on the reciprocal infection of the two hosts. 



Kki. 259. — Brohatidium rhododindri on Rhododendron ftrruffinciim. (v. Tulwuf phut.) 

A disease due to an Erobasid i inn is by no means uncommon 
on Vaccinium uligiiwm.rn (bog whortleberry). 2 Shoots of diseased 
plants are deformed, while their leaves become more or less 
thickened and assume a beautiful rosy colour. 

On Vaccinium O.rycoccos (true cranberry) (he shoots and 
leaflets also become thickened and rose-coloured. Rostrup dis- 
tinguishes this as a separate species (E.robasidi am an/cocci). 

Ex. andromedae Peck, produces on Andromeda po! if alia 
symptoms similar to those just described for the preceding 
species. (Britain and U.S. America.) 

1 Sadebeck (Bolnn. CenlraJhlaU, ISStit records it in large quantity near Harbnrg. 
This is the host-specics given by Masses ( liritinh Fuiit/iti- F/ora, 189*2). 

- Tubeuf. “ Mittheilungen.” Zeilnch. f. /'pnnzeukrankheileti, 1893. 


EXOBASIDIUM. 


427 


Ex. rhododendri Cram. (Britain and U.S. America). This 
causes gall-like outgrowths on the leaves of the Alpine- rose 
(. Rhododendron ferrugineum and Rh. hirsutum). The swellings 
may be small and fairly hard, or, attaining the size of cherries 
or plums, they may be soft and spongy so that they shrivel 
up soon after the twig is cut ; in colour they are yellowish- 
white, but on the side exposed to sunlight become rose-red ; 
the Exobasidium- galls may even be formed on the small rolled- 
up leaves caused by attacks of mites. 

Ex. Peckii Hals . 1 [This species occurs in the flowers of 
Andromeda Mariana in the United States. It is confined 
almost entirely to the inflorescences, and causes considerable 
distortion. The bell-shaped corollas are replaced by ones quite 
polypetalous, and the ovary becomes raised above the re- 
ceptacle.] (Edit.) 

The following five species have been recorded on Ericaceae 

in America : 

Ex. azaleae Peck. On Rhododendron nudiflorum. 

Ex. discoideum Ellis. On Rhododendron viscosum. 

Ex. decolorans Hark. On Rhododendron viscosum and R. occidentals. 

Ex. arctostaphyli Hark. On Arctostaphylos pungens. 

Ex. cassandrae Peck. On Cassandra calyculata. 

Other species to be mentioned are : 

Exobasidium ledi Karst. On Ledum palustre. 

Ex. Warmingii Rostr. (U.S. America). This occurs on Saxifraga Aizoon, 
S. hryoides , S. aspera, etc. ; it causes marked hypertrophy of the leaves, and in 
this way, as well as by its many smaller spores, is distinguished from : 

Ex. Schinzianum Magn. On the leaves of Saxifraga rotundifolia, causing 
whitish spots which soon become brown and die. 

Ex. symploci Ellis. On Symplocus tinctoria in North America. 

Ex. graminicolum Bres. On leaves of various grasses, e.g. Rrornus, 
Arrhenatherum, etc. 

Ex. lauri Geyl. 2 is said to produce branched outgrowths of over three 
feet in length on Laurus nobilis and L. canariensis in the Canary Islands. 


Urobasidium rostratum Ghgn. occurs on the “ witches’ broom,” out- 
growths caused by Taphrina cornu-cervi Ghgn. on Aspidium aristaturn 

in India. 


1 Halsted, Bulletin of the Torrey Club, xx., 1893, p. 437. 

-Geyler, Botun. Zeitung, 1874, p. 322, PI. VII. 


428 


BASIDIOMYCETES. 


HYPNOCHACEAE. 

Hypnochus. 

The mycelium forms a cobweb-like covering on living or dead 
parts of plants. The sporophores take the form of superficial 
coatings composed of club-shaped basidia developed on a felted 
hymenial layer of fungal tissue. Each basidium gives off two 
to six colourless smooth-coated spores from fine sterigmata. 
Some species are parasitic, and cause disease. 

Hypnochus cucumeris Erk. 1 In 1882 Frank found at Berlin, 
on the surface of withering and dying cucumber-plants, greyish 
coatings of the hymenial layers of this fungus. They occurred 
principally near the base of the stem, and caused its partial 
destruction. The symptoms consisted in leaves becoming rapidly 
yellow from tip to base, and dying off the plant, the lower 
first. Only cucumbers w r ere attacked, and no further stages 
could be observed on the killed plants. 

Hyp. solani Prill, et Del. 2 Fine grey crusts, consisting of 
the hymenial layers of this fungus, were found by these investi- 
gators on potato-plants ; there was, however, no injurious effect 
on the crop-yield. 


Aureobasidium. 

Aureobasidium vitis Viala et Boyer. 3 The cause of a vine 
disease which has done considerable damage in southern France 
on several occasions since 1 882. The grapes when attacked show 
spots, then shrivel up, their interior becoming completely per- 
meated by a colourless septate and branched mycelium. On 
rupture of the epidermis, a firm yellow tissue emerges, and 
thereon a hymenial layer is developed. The basidia are thick 
and club-shaped, with a varying number of short sterigmata ; 
these give off cylindrical unicellular light-yellow spores slightly 
curved in shape and with rounded ends. Leaves are also attacked, 
and fall off after gradually assuming a deep red colour. If 
this occurs in April, or early in May, the fruit never attains 
any size. 

'Frank, Hedwigia , 1883 ; and Berirhh d. dcuturh. bolnn. Of •«., 1883. 

4 Prillieux nnd Delacroix, Bulletin <!' In Sor. my col. d< France, 1891. 

s Viala and Boyer, Compl. raid. 1891, p. 1148, and xix., 1894, p. 248: .1 mini . 
de I'Ecoh nnt. d'agric. de. Montpellier , vi., 1891. 


THELEPHORA. 


429 


THELEPHOREAE. 

Thelephora. 

The sporophores of this genus assume very varied forms, from 
simple incrustations to mushroom-like structures. They consist 
of two layers only, the middle one being absent. The basidia 
are club-shaped and produce four roundish or oval, hyaline or 
light-coloured spores. 

Thelephora laciniata Bers. is not a true parasite, yet it is a 
dangerous enough enemy to trees. In damp situations, it is 
common and thrives, growing over young trees and so enveloping 
them with its sporophores that suffocation ensues. (Britain and 
U.S. America.) 

Th. pedicellata Schw. has been reported from America 1 as a dangerous 
parasite on apple, Quercus coccinea, and a palm. 

Th. perdix Hartig, a parasite on oak-wood. (See Stereuin frustulosum.) 

Helicobasidium Mompa. Ichik.- This is injurious to the mulberry tree 
near Tokyo, Japan. It first attacks the roots, and in consequence the 
growth of shoots is arrested, the young leaves die off, and gradually death 
of the tree follows. The mycelium permeates the tissues of the host, and 
forms an external velvety coating of basidia. 


Stereum. 

Sporophores generally differentiated into three layers, and 
forming leathery or woody encrustations, or flattened hemi- 
spherical structures attached by one edge only. 

Stereum hirsutum (W.) Fr. White-piped or yellow-piped oak. 
(Britain and U.S. America.) A very common fungus, occurring as 
a saprophyte on dead branches, on boards, and posts of various 
kinds of timber, as well as parasitic on living wood, particularly 
on oak. 

The sporophores first appear as crusts, later they become 
cup-shaped ; externally they are brown and roughly hairy with 
acute yellowish margins. The smooth hymenial layer is orange- 
red and marked by zones. Between the sterile leathery sporo- 
phore and the hymenial layer there lies a firm white 
intermediate tissue. 

1 Galloway, Journal of Mycology, vi., p. 113. 

2 Nobujiro Ichikawa, “A new hymenomycetous fungus,” Jour, of College of 
Science. Imperial University, Japan, 1890. 


430 


BASIDIOMYCETES. 


R. Hartig 1 has investigated in detail the phenomena accom- 
panying the wood-destruction in the oak. This begins in the 
branches and extends in white or yellow concentric zones 
throughout the stem, so producing that appearance which has 
given rise to the name “ fly-wood.” Portions of the wood appear 
only white-striped, other parts have a more regular yellowish- 
white colour. In the white strips the wood has been transformed 
into cellulose and the middle lamellae of the walls dissolved out; 
that of the yellow parts has not undergone this transformation 
into cellulose, but the destruction has begun from the cell-cavity. 



Fio. 2fi0. — sure u hi jnettuloium. Destruction of Oak-wood. Longitudinal 
section showing the brown wood with isolated hollow spots containing white 
mycelium, (v. Tubcuf phot.) 

Stereum frustulosum Fries. (Thelephora perdix Hartig ). 2 

(Britain and U.S. America.) The sporophores form greyish- 
brown plate-like crusts with concentric markings; they are small, 
never exceeding the size of a finger-nail, but generally occur 
in numbers together. The hymenial layer is composed of club- 
shaped basidia beset with hair-like outgrowths; some of the 
basidia produce four spores, others are sterile and grow on to 
form the hymenial layer for the following year. 

1 R. Hartig, Zrriftznn rxchf inu nqr n tl. Ho!z> s, 1 STS, Plate Will. 

2 R. Hartig. Zersi-tzHiHjstrHcheinnnejcn, Plate XIII. 


STEREUM. 


431 


CLAVARIEAE. 


Typhula. 

Sporophores filamentous, and, as 
a rule, developed from sclerotia. 
Basidia, with four colourless smooth- 
coated spores. 

Typhula graminum Karst . 1 This 
appeared on wheat plants in Sweden, 
killing them and forming yellow 
sclerotia ( Sclerotium fulvum Fr.). 


Fig. 2G1 . — Stereum frv.stv.losu.rn. 
Later stages of Oak-wood destruc- 
tion. Longitudinal section showing 
holes in the timber, (v. Tubeuf 
phot.) 



The very characteristic destruction of oak-wood caused by 
this fungus was investigated by R. Hartig. The diseased wood 
has a uniform dark-brown colour, broken at intervals by white 
rounded spots or hollow cavities , 
hence it receives the name of 
“ partridge-wood.” In the white spots 
the wood has by the action of the 
mycelium become transformed into 
cellulose, the middle lamellae and 
starch-grains being dissolved out. In 
the neighbourhood of old eaten-out 
cavities the process of decomposition 
is slightly changed, so that the cell- 
walls disappear without previous trans- 
formation into cellulose. 


HYDNEAE. 

Hydnum. 

Sporophores very variable in form and structure, ihe 
hymenial layers are spread over teeth-like projections. The 
basidia bear four white spores. 

Hydnum diversidens Fr . 2 (Britain). The sporophores form 
yellowish-white crusts or brackets, with spiny outgrowths on 
the lower side. The hymenial layer consists at first of basidia 
only, later, however, hyphae grow up through it and build 

1 Eriksson, Landtbr. AJcad. Hand. v. Tidskr., 1S79. 

2 R. Hartig, Zersetzungserscheinuvgen. 


432 


BASIDIOMYCETES. 


over it a new hymenium ; this is continued for some time so 
that the sporophore consists of successive layers, and the spiny 
outgrowths become much thickened. Infection, as was experi- 
mentally shown by Hartig, takes place on wounds. 

The wood-destruction, consisting of a white-rot, was studied 
by Hartig, chiefly on the oak and beech. It begins by the 



Fio. *262. — PolyporuA igniariu*. Causing death of a White Alder plantation at 
Petneu, Stanzer Thai, Tyrol. The stoma boar sporophores, and dio from abovo 
downwards, (▼. Tubeuf phot) 


appearance of yellowish longitudinal bands (not white as with 
Sterrnm hirsutmn), and extends gradually till the wood becomes 
uniformly yellow. The mycelium causes the inner layers of 
the cell-walls to swell gelatinously without previous transfor- 
mation into cellulose, and finally to dissolve out leaving the 
middle lamellae longest intact. 


HYDNUM. 


433 


Sistotrema fusco-violaceum 
Schrad. (Britain.) Tliis according 
to Skiljakow 2 is parasitic on living 
pines, entering by wounds, and 
carrying destruction throughout 
the wood. 


POLYPOREAE. 


Polyporus. 

Sporophores large and 
usually shaped more or less 
like a hoof or small bracket. 

The sporogenous layer is com- 
posed of cylindrical tubes, 
which generally occupy the 
lower surface of the sporophore. 

The substance between the tubes is different from that of the 
rest of the sporophore. 

Polyporus (Fomes) igniarius (L .). 3 (Britain and U.S. America). 
Sporophores on living stems of oak, alder, apple, willow, and other 


Fig. 263 . — Polyporus igniarius on Oak. At 
the upper end a wood-pecker’s nest-hole, (v 
Tubeuf phot.) 



Hydnum Schiedermayeri Heufl. (U.S. America). Sporo- 
phores fleshy, with a sulphur-yellow colour both outside and 
inside, and with a smell of anise. They occur on living 
apple-trees, less frequently on other species of Pyrus. Accord- 
ing to Schroeter, Thiimen, and 
Ludwig, the mycelium spreads 
through the stems and kills 
the trees. 

Thiimen 1 thus describes the 
diseased wood of the apple : “ It 
has a greenish-yellow colour, 
which passes over gradually 
to the normal colour of the 
wood : it becomes soft and 
friable, smelling, like the 
sporophore, faintly of anise.” 


1 Thumen, “ Ein Apfelbaum-Schailling.” Zeitsch. f. Pflanzenkrankheiten, 1891. 

2 Skiljakow, Scripta botan. horti univerxitatis Pelropolitancie, 1890. 

3 R. Hartig, Zersetzungserscheinungm, PL XV. and XVI. 

2 E 





434 


BASIDIOMYCETES. 


deciduous trees . 1 They are brown or grey in colour, tuber-like or 
hoof-shaped, and continue to grow for several years ; the upper 



*v. Tubeuf ( For*// -naturiri**. ZtiUchrifl, 1893) describes a plantation of Alum 

tnrana in lyrol, which was being killed out bv this fungus (Fig 262). It i* 
a common British species. (Edit.) 




POLYPORUS. 


435 


side is concentrically marked, and has a stone-hard coating which 
is generally more or less cracked ; several zones and layers of 
tubes will be found when the sporophore is cut in section. 

This fungus produces a white-rot in the wood, and is one of the 
most common and dangerous of wound-parasites. The wood 
attacked by the mycelium is at first dark in colour, then 
yellowish-white and soft. According to Hartig, a delicate 
mycelium fills up the elements and eats away the inner layers 
of the walls ; then the middle lamellae are transformed into 
cellulose and absorbed by it (Fig. 264). 

Polyporus fomentarius (L.) ( Fomes fomentarius (L.) Fr.) 1 
(Britain and U.S. America). “ Tinder-fungus.” Sporophores 
broad and shaped like reversed brackets or hoofs. Their upper 
side, at first brownish and velvety, becomes afterwards smooth, 
grey, and marked with broad concentric zones. The margin 
is rounded and uniformly grey. The pore-layer is smooth and 
greyish-brown. A longitudinal section shows a homogenous 
tinder-like mass, covered on its lower surface by layers or 
zones of pores. 

The tinder-fungus is parasitic on beech, elm, and mountain 
maple. It is particularly common in beech-forests, and was 
even more so at one time when the infected trees were allowed 
to remain standing. The sporophores may be found on living 
stems, on remnants of trees broken by wind, and on felled 
trees. For some distance above and below the seat of the 
sporophore runs a furrow on the stem, marking a tract where 
the mycelium has penetrated to the cambium and killed it, so 
that growth in thickness ceases (Fig. 266, a). 

The mycelium causes in the wood a white-rot of a light 
yellow colour. Where the wood is still firm, though diseased, 
it will be found to be divided into cubical portions by white 
tracts of mycelium which run both radially and vertically. A 
very characteristic feature of the destruction consists of broad 
white leathery bands of mycelium, formed in a radial direction 
through the wood ; these are best seen on stems shattered by 
storm, or on wrought timber. 2 

1 Rostrup, Tidsskrift pa Skovburg, 1S83. Tubeuf, “ Mittheilungen,” Alley. 
Forst-. u. J ayd- Zeitung , 1887. A common British species. (Edit.) 

" Krull (Schle-s. Ges. f. vaterland. Knit., 1893) distinguishes a gelatinous mycelium 
and a cushion-mycelium. 


436 


BASIDIOMYCETES. 


Tinder, prepared from the soft central part of the thick 
sporophores, was at one time used, with the help of steel and 
Hint, for procuring flame. It is very effective in stopping 



Fio. 265. -iScene in t lie Bavarian forost near BischofTsreut. In the foreground, a living 
Beech with seven sporophores of Pofy/torus/onunfariut. (v. Tubcuf phot) 


haemorrhage from cut blood-vessels, and is still used in surgery. 
The larger pieces can be manufactured into caps, gloves, vests, 


POLYPOKUS. 


437 


and hose. The privilege of collecting the tinder-fungi was 
rented out and regarded as a source of forest-revenue, while the 
tinder-industry was formerly an impoi’tant one in many districts, 
where sporophores were more frequent and larger than now. 

Measures against this fungus have already been considered 
in our General Part (§ 12). 



a b 


Fig. 266. — Polyporu* fomentarius on living Beech, a, A furrow extending 
above and below the insertion of the sporophore. b, An injury produced by 
tearing of the wood in felling, (v. Tubeuf phot.) 

Polyporus sulphureus (Bull.) 1 (Britain and l .S. America). 
The sporophores are flat and soft, the upper side being bright 
orange-red and the lower sulphur-yellow. They last only for 
one year, hence are small ; they frequently occur in masses, 
one above another in tiers. After death they lose colour, 
become brittle, and are easily detached. According to De 

1 R. Hartig, Zersetzungserscheinvngen. A very common species in Britain. 
(Edit. ) 


438 


BASIDIOMYCETES. 



Fio. 207. — Polyporus sulphur? u a on a Willow ( Sali.< alfm) at Hirschau, near 
Munich, (v. Tubouf phot.) 


POLYPORUS. 


439 



Sevnes , 1 three other kinds of spores are produced in addition 
to basidiospores. 

Willow, poplar, oak, sweet chest- 
nut, alder, ash, hazel, pear, cherry, 
robinia, larch, silver fir, etc., are 
common hosts of this parasite. 

Wood infested by the mycelium 
darkens in colour, exhibiting a red- 
rot. Vessels and all clefts or spaces 
become filled with white felted 
masses of mycelium. The wood, in 
course of destruction, becomes richer 
in carbo-hydrates, and the walls of 
the wood-fibres shrink so that fis- 
sures with an upward right to left 
direction are formed, but do not reach Flo . 2 gs .-Poiy-poms miphureu*. 
the middle lamellae. Finally the a " d 

wood becomes dry, brittle, and powdery. 

Polyporus borealis (Wahlenb.) Fr . 2 (Britain and U.S. 
America). Sporophores annual, white, and fleshy ; the upper 



Fig. 209 . — Polyponts sulphureus. The white mycelium forms concentric zones 
and radial lines on the cross-section of Oak. (After R. Hartig.) 


surface is shaggy when fresh, and no internal zones are exhibited. 
The shape is somewhat cushion or bracket-like, but very variable ; 

1 De Seynes, Annul, de Sci. nat . , Ser. V., Yol. i., 1864. 

2 R. Hartig, Zersetzungserscheinwngen, PI. X. 


440 


BASIDIOMYCETES. 


many generally grow near each other. The pores have a torn 
margin and cystids are frequent between the basidia. 

The sporophores are common in spruce plantations, and are 
accompanied by a very characteristic wood-destruction. The 
wood, in the earlier stages, becomes brownish-yellow and inter- 
sected by radial and vertical canals filled with a white mycelium 
^ig. 2 70), Gradually, however, it breaks up into small cube- 



Fio. 270. — Polf/poru* l>or(aliA. Destruction of 
Spruce-wood. The white mycelium is present, 
dividing the decayed wood into cubical pieces, 
(v. Tubeuf phot.) 



Fm. 271 .— Polvporus horrali*. Later stage 
<»f destruction. The Spruce- wood is broken 
up into cubical pieces, and the mycelium has 
disappeared. (v. Tubeuf phot.) 

(Fig. 

Ollt- 

and 

( I Brit ain 
like 
of the 

Rritish species. 


like pieces, particularly evident when the wood is broken 
271). The cell-walls are dissolved from the cell-cavity 
wards, the lignified wall being first converted into cellulos< 
disappearing, finally the middle lamella. 

Polyporus dryadeus hr. 1 (7*. p.sox/on/u in tins Bull.) 
and l .X. America). Sporophores, annual, large, shaped 
tubers or hoofs, and generally situated towards the base 

1 R. Hnrtig, Zersetzinii/nerscheimtHgen, PI. XVII. A common 



POLYPORUS. 


441 



stems of oak-trees. At first they are soft, later hard and brown 
with grooves on the upper side. The dark heart-wood of the 
oak exhibits white or yellowish longitudinal stripes of rotten 
wood converted into cellulose (Fig, 272). In the white portions 


Fic. 272 . — Polyporus dryadeus. The mycelium forms longitudinal stripes 
in the Oak-wood. (v. Tubeuf phot.) 


the destruction is more complete than in the yellow, where dis- 
solution of the lamellae has not as yet taken place (Fig. 273). 

A simultaneous destruction of the wood by P. dryadeus and 
P. igniarius may occur (Fig. 274); in this case, the medullary 



442 


BASIDIOMYCETES. 


rays appear snowy white at the place where the two forms 
of rot meet ; this is due to an accumulation of starch left 
after the cell-walls have been almost completely dissolved. 

Polyporus iPoria) vaporarius (l’ers .) 1 (Britain and U.S. 
America). The sporophores are white, and have a pungent 
odour ; they form crusts (never brackets) closely adherent to 
dead substrata, especially to beams and other timber in buildings, 



Fin. *27:i. Potyporu * dryadcv*. La ter 
stage of decay oi Oak-wood. The darker 
places still consist of firm brown wood ; 
the white, however, are soft cellulose, 
(v. Tubeuf phot.) 


Fin. *274. - Pol vporn* dry ad< tut and Poly 
porn* ••iniarius. Destruction of Oak- 
wood under the combined agency of 
both fungi. The wood is yellowish and 
perforated ; the medullary rays are 
snowy* white, from the accumulation of 
unchanged starch, (v. Tubeuf phot.) 



where this fungus does great harm. They are also found, how- 
ever, on bark of living stems of spruce and Hr. The destruction 
takes the form of a red-rot, the wood attacked becoming red- 
brown, cracked, and soft. The mycelium is found in stems and 
roots of trees : in cracks in the wood and below the bark, and 
on the surface of timber in buildings, it forms fan-shaped strands 
of a permanent white colour. The mycelial strands of the 
“dry-rot fungus” (Miruliiis facrymaii.'i) differ from it in being 


Very common in Britain on dead wood, less so on living trees. (Edit.) 


POLYPORUS. 


443 



at first white but becoming grey, and in exhibiting an internal 
differentiation which those of P. vaporarium do not. 1 

The hyphae in the course of their growth do not seek out 
the pits, but grow straight through the walls and bring about 
dissolution of the middle lamella for some distance around. At 
the same time numerous short oblique fissures in the walls are 
produced vertically one over the other, especially in the elements 


of the thick-walled autumn wood. (Compare with P. sistotre- 
rnoides, Fig. 280). The phenomena accompanying destruction of 
wood by this fungus are so characteristic that Conwentz" could 
distinguish it quite clearly in tree-remains enclosed in amber. 

Brefeld succeeded by artificial culture of the spores, in raising 
a mycelium on which basidia were formed, at first directly, 
afterwards from large sporophores. 

Polyporus squamosus (Huds.). (Britain and U.S. America.) 


Fig. 275. — Polyporus squamosus on Acer NeguwJo. The three upper sporophores 
are borne on a separate piece of wood, from which a fourth has been cut off. 
(v. Tubeuf phot.) 


1 R. Haitig, Der echte Hausschwamm, Berlin (Springer), 1S85. 
2 Conwentz, Monographic d. baltischen Bernsteinbaume, 1890. 


444 


BASID IOM Y CETES. 



Sporophores annual., occurring from spring to autumn ; at first 
tender and fleshy, later leathery or almost woody. In form 
they are short-stalked, flat, semi-circular or kidney-shaped, and 
attached by one edge ; they may also be stalked and circular 
or cup-shaped. Their upper surface is yellowish, with flat brown 
scales arranged in concentric lines. The hymenial layer is 
continued well on to the thick fleshy stalk of the sporophore; 
it is yellow in colour, and consists of short angular pores. 


Flo. 276. Polyporu* hitpidu » on pieces of living Ash. (v. Tubcuf phot.) 

1 lie spores are spindle-shaped and colourless. The fungus is 
especially common on living hazel, ash, species of maple, beech, 
mountain ash, horse-chesnut, elm, oak, willow, pear, lime, etc. 

The wood of the specimen in Fig. 275 exhibited extensive 
white-rot, the inner parts being completely converted into a 
soft white spongy mass of mycelium. 

Polyporus hispidus (Bull.). 1 (Britain and U.S. America.) 
Sporophores annual, soft and spongy, with a rough brown upper 

'A very common form on ush trees in Britain. (Edit.) 


POLYPORUS. 


445 


surface, and a smooth yellowish hymenial surface. They are 
large and flat, the thickest part being at their insertion 
(Fig. 277). Several frequently occur on the same stem, especially 
if wounds or frost injuries are present. The spores are brown 
and roundish. Conidia are said, by Schroeter, to be formed on 
the upper surface of the sporophores. 

This species is a deadly enemy of fruit-trees, especially 
apple. In the vicinity of Munich the sporophores are common 
on ash. Schroeter gives elm and plane as hosts, and Prillieux 



Fig. 277. — Polyporus hispidus. Longitudinal section through a living stem of 
Ash, and a sporophore of P. hispidus. The stem shows symptoms of wood- 
destruction, in that it becomes brown and has short white longitudinal and 
radial stripes, (v. Tubeuf phot.) 


and Delacroix state the fungus to be very dangerous to the 
mulberry in France. 

It causes 1 brown discoloration of the wood accompanied by 
characteristic short white lines in both radial and vertical 
directions, so that the wood becomes marked out in squares. 

Polyporus (Poria) laevigatus Fr. 2 Sporophores dark-brown 

1 Prillieux ( Bullet . de la Soc. mycolog. de France, ix., 1893), gives details of 
the destruction of the wood. 

2 Mayr, Botan. Centralblatt, xix., 1884. 


446 


BASIDIOMYCETES. 


and forming crusts on the bark of birch. Spathulate cystidia 
occur between the basidia. Spores colourless, and acutely ovate 
in shape. 

I bis is parasitic on birch. 1 lie mycelium kills and permeates 
the wood-parenchyma which forms the greater mass of the 
later-formed parts of each year-ring, with the result that the 
various year-rings of the wood separate from each other as 
concentric hollow cylinders. The mycelium varies according as 
its pabulum consists of cells just killed, or of wood, or of 
elements in the last stages of decomposition ; in this latter case 
it suffers from want of food. In woody elements in contact 


with air, or those destroyed 
by Polyporus betulinus, the 
mycelium is brown and 
forms vesicular tyloses 
similar to Ayarieus mclleus. 



Polyporus betulinus Fi . 

(Britain and U.S. America). 
The sporophores are annual, 
and emerge as spherical 
structures from the unin- 
jured bark, or from bore- 
holes of Beetles, or other 
wounds. \\ hen mature 
they are hoof-like or semi- 
circular and short-stalked : 
when dead they become 


Fig. 278.— Polyporu* betulinus on B'tuln vtrrucota 
The sporophore was developed horizontally on a 
fallen stem ; it is here, however, set up vertically 
and photographed from the lower side. (v. Tubeu'f 
phot.) 


soft and break off. 1 he upper side is light-brown in colour, the 
pore-layer is white. A section through the sporophore shows it 
to be white and homogeneous without zones. Lanceolate cystidia 
occur between the basidia. The spores are rod-like. The pore- 
lav ei and the upper brown layer are easily detached, and strips of 
the remaining tissue are sometimes utilized as razor-strops. 

This parasite frequents living birches, ultimately causing death. 
It is known to occur on both Betulci verrucosa and 11. pubescent 
in Britain, America, and Europe. Its parasitism and injurious 
results were first demonstrated by Rostrup. 1 Mayr 2 investigated 

, IRo !& ' Snyltesvamper Augreb pan Skovtraeeme,” Tid^hifl i*x Skor- 
hurt/, 188.5. • 1 

2 Mayr, Botan. CeiUra/blall, xix., 1SS4. 


POLYPORUS. 


447 


in greater detail the destruction brought about by its mycelium. 
He found that it penetrates lignified cell-walls, entering the living 
elements and causing their death; it spreads most rapidly in the 
vertical direction through wood, bast, and rind, growing through 
parenchyma and sieve-tubes, and even boring its way into the 
sclerenchymatous stone-cells ; it absorbs the secondary thickening 
by dissolving out first the ligneous incrustation, next the cellulose, 
while the middle primary lamella remains behind untouched. 

Polyporus (Fomes) fulvus (Scop.) (Britain). Sporophores 
woody and very hard, at first hairy but later smooth, dark, 
and cracked ; in form they are tuberous or triangular. In- 
ternally they show no stratification. The fungus is very common 
on living plum where it causes undoubted injury ; it also occurs 
on hornbean and aspen. 

Polyporus fulvus var. Oleae Scop. In northern Italy 
may be frequently observed a peculiar splitting of the stems 
of olive trees into two or more portions ; the fissures occur 
generally on the lower parts of the tree, and may extend so 
deeply that the stem appears to stand on stilts or props. 
Hartig 1 ascribes this phenomenon to the presence in the olive 
stems of the mycelium of Polyporus fulvus causing rotten places 
which are cut out by the Italian cultivators ; the disease, how- 
ever, continuing to make progress, it may be necessary in course 
of time to cut so deeply into the stem, that tracts extending 
right through may be removed ; this takes place all the more 
rapidly if several diseased spots are being simultaneously 
operated on. The destruction of the olive-wood by this parasite 
is similar to that produced by P. igniccrius on oak and other 
trees. The sporophores appear on rotten spots, but are gener- 
ally quickly removed by the cultivator. Infection takes place on 
wounds, hence it is advisable at once to apply tar after cutting 
out any decayed wood, and also to paint pruning-cuts or other 
exposed surfaces with tar. Neighbouring fruit-trees, liable to 
suffer from this same fungus, should be similarly treated, both 
for their own safety and that of the olive trees. 

Polyporus ( Fomes) Hartigii Allescher 2 (P. igniarms var. 

1 R. Hartig. “Die Spaltung der Oelbanme. ” Forstlich-naturwiss. Zeitschrift , 

1893. 

2 R. Hartig, Zersetzungserscheinungen, PI. VII. Forstlich-naturwiss. Zeit- 

schrift, 1893, p. 61. 


448 


BASIDIOMYCETES. 


pinuum Bresadola or P. fulvus Scop, of K. Hartig). Sporophores 
on silver fir, less commonly on spruce. Their form varies much, 
according as they occur on a branch or on the stem. In the 
former case, the sporophore forms a swelling below and on each 
side of the more or less horizontal branch. On the stem they 
are more or less bracket-like. The sporophores ^re reddish 

brown with a smooth upper surface on 
which zones are only faintly indicated 
or altogether absent. Internally they 
are of a brownish or tawny colour, and 
exhibit concentric strata, which do not 
extend into the pore-layer; they are thus 
distinguished from sporophores of P. 
ignicirius and others. The sporophores 
are very frequent on cankered stems of 
fir where the canker-spots afford easy 
entrance for the spores. 

The wood-destruction consists in a 
white-rot. The wood becomes yellowish- 
white with clear spots and line dark 
lines, especially where in contact with 
healthy parts. The mycelium is yellow- 
ish, and consists of thick hyphae with 
\ tv; lateral branches forming tangled masses 

uIHs which frequently fill up the cavity of 

the bordered pits. This mycelium gives 
off very fine branches which bore through 
the cell-walls and dissolve them in such 
a way that the middle lamellae disappear 
first and leave the remainder of the wall- 
thickening for a time isolated before it 
too is used up. In this way large holes are formed in the 
elements of the wood. 

Polyporus sistotremoides (Alb. et Schw.) yP. Schwcinitzii 
Fr. or P. mollis Fr. of 11. Hartig) 1 (Britain). Sporophores almost 
circular with a short thick central stalk ; while young they 
are light brown and spongy, but when older become dark brown 
and corky. The upper surface is downy ; the hymenial layer 
extends far down t he stalk, when young it is yellowish green, 

1 R. Hartig, Z(ratl'uuiiin-srheiium;)fn, 1*1. IX. 



Flo. 279. — Poh/i>nrut II nrtipii . 
Destruction of wood of Silver Kir. 
The decayed wood is yellow, but 
shows dark points and bl 
(v. Tubcuf pi 


points 
inot. ) 


POLYPORUS. 


449 


but later becomes brown, and, on being touched, deep red. The 
spores are white, and various forms of hairs occur among the 
basidia. Young sporophores appear as little brown cushions on 
felled timber, also on living stems of pine, and, according to 
Magnus, on Weymouth pine. 

The disease generally makes its first 
appearance in roots and lower parts of the 
stem, spreading thence into higher parts. 

Diseased wood has a characteristic odour of 
turpentine ; it has a reddish-brown colour, 
and, as destruction proceeds, it gradually 
shrinks and disintegrates till it becomes so 
soft as to be easily powdered between the 
fingers. Where broken over, the wood is 
often covered with a thin white coating of 
mycelium incrusted in resin so as to appear 
like chalk. 

The mycelium penetrates the cell-walls 
in all directions. A very characteristic 
feature of this parasite is furnished by 
shrinkage-fissures in the thick walls of the 
tracheids of the summer- wood (Fig. 280). 

These are numerous and run upwards from 
right to left extending through the whole 
wall to the outermost layers. They differ 
from the fissures in tracheids destroyed by 
P. vaporarius, in that they run round the 
whole circumference of the cell, instead of 
being small and set vertically above each 
other. 

Polyporus (Fomes) pinicola (Sw.) (U.S. 

America). Sporophores thick, hoof-like or 
bracket-shaped, with a smooth dark-grey upper side and a bright 
red rounded margin. The hymenial layer is smooth and yellowish, 
the spore-powder white. In section the sporophores are white. 
The species is frequent on living stems of spruce, pine, and fir, 
also on birch and cherry. 

Polyporus (Fomes) marginatus Fr. (U.S. America). Sporo- 
phores with red margins, and otherwise very like those of the pre- 
ceding species, yet generally much larger, and more extended. 



Fig. 2S0. 


of 


Tracheid 
Pinus destroyed by Polyj>oru$ 
sistotremoides. The cellulose 
has been for the most part 
extracted, and the walls con- 
sist of lignin (wood -gum). 
Cracks occur in the dry 
secondary wall, while the 
wall (a, b) remains intact. 
The spiral structure of the 
secondaiw wall causes cross- 
ing of the fissures in the 
walls of adjoining cells at 
the bordered pits, c, and at 
bore -holes, d, e ; where 
neither pits nor holes are 
present the fissures are 
simple,/. (After R. Hartig.) 


450 


BASIDIOMYCETES. 


The two species are held by many authors to be identical. 
It occurs chiefly on stems of beech, also on oak and birch. 
In regard to its parasitism nothing further is known. 

Polyporus (Fomes) annosus Fr. (Trametes radiciperda 
Hartig 1 ) (Britain and U.S. America). The sporophores vary 
much in form, according as they occur more above or more 
below ground on tree stems, or on timber in mines. The 
upper surface is brown and marked in zones, the margin being 
lighter. The section through the woody sporophore is white. 
The hymenial layer is also white. Spores ovoid and colourless, 
germinating easily in water. In artificial cultures, Brefeld 
states 2 that they produce only conidia. 



Fin. 281 . -Polyporu* annotu* Fr. (Tranutt* radiciperda Hartig). Stool of a 
forty-year Spruce, which 1 i;in been dead for two or three years. The Bporophore 
is several years old. a, a, White open-pored layer forming over the dead basidial 
layer, h , b ; at c a narrow strip of wood still remains firm, the remainder is 
completely destroyed and rotten. (After R. Hartig.) 

This species was first investigated in detail by R. Hartig , 1 
and is described by him as (he most dangerous of all parasites 
in the conifer forest. It is most frequent on Conifers, e.g. pine, 
Weymouth pine, spruce, silver fir, Douglas fir, balsam fir, 
juniper, and Thuja ; it also occurs on various broad-leafed trees, 
e.g. beech 3 and hawthorn. 

1 R. Hartig, ZeraetzungterschcininKjin, 1*1. I. -IV. 1 1 '/«•/(/,'_>/■ Knuikheiten, PI. 
III. Zeitxrhrift f. Forat-und Jcujd-wexeii, 1889, p. 4'JS. liotan. Centra/ldatt, 
xi. ii., 1890. 

2 Brefeld, Schimmelpilse, Hi'ft 8, 1889. 

Rostrup, Afhildning o<j /ieab'irelse af dv J'avlitjate Snyllesrampe, 1889. 


POLYPORUS. 


451 


The mycelium penetrates both bast and rind causing a very 
acute red-rot in the wood, so that death of the tree attacked 
rapidly follows. The disease makes its appearance on plants 
of all ages, and in forests of spruce or pine causes gaps 
which rapidly extend in a centrifugal direction. The roots 
and lower parts of the stem are generally the parts first 
attacked. On the roots, the parasite is easily distinguished, 
even in the absence of sporophores, 
by the very delicate white mycelial 
membranes formed between the 
bark-scales. Destruction of the 
wood becomes first evident by the 
appearance of vertical dark lilac- 
coloured stripes indicating the stage 
when the parenchyma cells are 
killed. At a later stage, the wood 
becomes brown, and shows isolated 
black spots with white margins 
(Fig. 282). These last consist of 
coils of dark mycelium surrounded 
by wood from which the incrusting 
substance has been dissolved away, 
leaving only cellulose, readily dis- 
tinguished by turning blue on 
treatment with chlor-zinc-iodine ; here too, the middle lamellae 
are ultimately dissolved out, so that the elements become isolated. 
A colourless mycelium may also be found in the other parts 
of the wood, both inside the elements, and extending in all 
directions through the cell-wall, leaving holes where it itself 
has disappeared. Dissolution of the lignifying substance pro- 
ceeds from the cell-cavity, the middle lamella remaining 
intact till the last. The resin of the decayed wood passes over 
into all healthy parts and flows from the bark of diseased 
stems as a resin-flux. 

The most effective method for combating the ravages of 
this parasite is isolation of infected areas. In one case which 
I investigated in Baden, several spots in the forest formed 
very evident starting points, and sporophores were everywhere 
present at the base of stems amongst the moss. Such spots 
should be enclosed by ditches with vertical sides, and deep 



Fig. 282. — Polyporus annosus. Destruc- 
tion of Spruce-wood. Longitudinal sec- 
tion showing white (cellulose) spots with 
black (mycelium) centres, (v. Tubeuf 
phot.) 


452 


BASIDIOMYCETES. 


enough to cut through all roots, care being taken to leave no 
diseased stems or roots outside the circle ; after remaining open 
for a time, the ditch must be refilled with soil to prevent 
development of sporophores on the exposed roots. Diseased stems 
should be felled, and, along with all root-remains, burned on 
the spot, where there is no risk of forest fire ; failing this, they 
and their stumps should be deeply covered over with soil, to 
prevent development of sporophores. 

The following species of Polyporus have been observed on 
living trees, but details in regard to their parasitism and mode 
of destruction are still wanting : 

P officinalis Fr. On larch, chiefly in Russia, but also in France and 
Switzerland. The sporophores are white irregular masses, and at one time 
were used in medicine. The mycelium forms bands in the wood similar 
to those of P. sulphurous. 

P. albus (Corda), according to Ludwig 1 * is a cause of a disease of Conifers, 
which extends from the root upwards. (U.S. America.) 

P. spumeus (Sow.). On apple trees. (Britain and U.S. America.) 

P. furnosus (Pers.). On willow, ash, maple, and other broad-leaved trees. 
(Britain and U.S. America.) 

P. picipes Fr. On willow and other broad-leaved trees. (Britain and 
U.S. America.) 

P. (Fomes) cinnamomeus Frog. On cherry trees. (Britain.) 

P. radiatus (Sow.). On alder (.1. incana), birch, and beech. (Britain and 
U.S. America.) 

P. (Fomes) ribis ( F r.). On blackcurrant and gooseberry shrubs. (Britain 
and U.S. America.) 

P. (Polystictus) hirsutus Fr. (Britain and U.S. America). On living 
hornbeam, alder, oak, birch, and service. A variety, scruposus, is common 
and injurious on cherry. 

P. ulmarius Fr., is, according to Cavara,- parasitic on living elm near 
Pavia. (Britain and U.S. America.) 

P. (Fomes) nigricans. On birch. (Britain and U.S. America.) 

P. salicinus (Pei's.). A dangerous enemy of willow. 3 (Britain and U.S. 
America.) 

Rostrup 4 gives Corticium comedens as a wound-|iarasite of oak and 
alder. 

Hartig describes Fistulina hepatica, the liver-fungus, as causing a dark- 
brown colour in oak-wood. 

1 Lndwig, Lehrbuch d. niederen Kryp/oijamen. 

*Cavara, Revue Myro!., 1891. 

:l Tursky, Russian translation of R. Hartig's “ Lehrbtirh d. liaumh'aukheiten. " 

4 Rostrup, Fortsalle Underscsjclser, 1S83. 


TRAMETES. 


453 


Trametes. 

Sporophores as in Polyporus, except that the substance 
between the pores does not differ from that of the rest of the 
sporophore. 1 

Trametes pini (Brot.) Fr. 2 Bing-scale of Pine. This is a 
dangerous forest parasite in Northern Germany ; also in Britain 
and U.S. America. On the pine the sporophores develop from 
branch-scars, and assume a bracket form. The fungus has also 
been observed on spruce in Bavaria and elsewhere, but in this 
case, the sporophores are more frequently found as a coating 
over the bark on the under side of a branch. Larch, silver 
fir, and the Douglas fir (in America), have also been mentioned 
as hosts. 

The sporophores are brown and woody, and continue to form 
annual hymenial zones for a number of years. The hymenial 
layer consists of pore-tubes lined with basidia, between which 
thick-walled cystidia are formed. The spores are elliptical, and 
on germination penetrate into wounds or broken branches not 
protected by an outflow of resin. The older branches of pine 
and larch have a central heart-wood from which no resin is 
secreted, and these branches, when broken over, offer the neces- 
sary access to the germinating spores ; for this reason, infection 
takes place most frequently in old plantations. The mycelium 
spreads through branch anil stem, particularly upwards and 
downwards in the same year-ring. In this way longitudinal 
stripes and peripheral zones are formed in the wood, giving rise 
to the popular name “ ring-scale. 1 ’ Single hyphae bore through 
the cell-walls, and a ferment secreted by them dissolves 
the incrusting substance, so that walls affected show the re- 
actions for cellulose almost at once. A very characteristic 
feature is the appearance of isolated white spots or holes, indi- 
cating where the wood, after becoming cellulose, has been 
dissolved out entirely. The middle lamellae are dissolved out 
first in attacks of this fungus, the tertiary lamellae remaining 
longest intact (Fig. 12). The dark centres of mycelium inside 

1 The distinction between the genera Polypoms and Trametes is badly defined. 
A reinvestigation of the systematic relationships of the whole group of Polyporeae 
would in fact be advisable. 

-R. Hartig, Zersetzungserscheinungen, PI. V. and VI.; Wichtige Kranhheiten , 
PI. III. ; Lehrbuch d. Baumhraiikheiten, 1894 (English translation by Somerville). 


454 


BASIDIOMYCETES. 


white wood-spots, so characteristic of Pulyporus annosus (Tram, 
radiciperda), appear only rarely in this species. 

The destruction of spruce and fir goes on from pith to bark ; 
in the pine, however, it seems to be confined to the heart-wood, 



Fig. 283. Trnmett* pini on Spruce (Pica i 
< .'Ttlm). Sporophore on the stein bon oath u 
snag-branch. (v. Tubeuf phot.) 


Fig. 284. Ti'&nirtf* pun on Spruce. 
Board showing the characteristic 
white cellulose-spots in the wood, 
(v. Tubeuf phot.) 


and is prevented from entering the sap-wood by a firm zone 
permeated with resin. 

Remedial measures are the removal of all diseased stems 


Tit A METES. 


455 


at thinning; and the prevention of unnecessary injuries to living 
branches or stems. 

Trametes suaveolens (L.), common on dead willow, is also 
reported as parasitic on living stems. (Britain and U.S. America.) 


AGARICINEAE. 

Agaricus. 

Sporophores umbrella-shaped and fleshy, and decaying soon 
after discharge of the spores. Hymenium on the under side 
of the umbrella, and spread over a series of radiating gills or 
lamellae, easily divisible in a longitudinal direction. 

The genus is divided into sections and subgenera distinguished 

o o o 

by the colour of the spores ; the Coprinarii are black-spored ; 
the spores of the Pratelli are dark purple, brownish-purple, or 
dark brown ; of the Dermini brown, yellowish-brown, or orange ; 
of the Hyporhodii rosy or salmon-coloured ; of the Lcucospori 

white. 

Agaricus (Armillaria) melleus Vahl. 1 (Britain and U.S. 
America.) The honey-fungus or “ hallimasch.” The sporophores 
are present in numbers towards the close of summer on tree- 
stools of all kinds, and on the bark of dead or living Conifers ; 
also on timber, and even on earth. The fleshy stalk is somewhat 
thickened towards its base, and towards the upper part bears 
the membranous yellowish annulus (Fig. 286). The cap sur- 
mounting the stalk is honey-coloured or brownish with dark 
scales. The spores are white and bestrew adjacent objects with 
a mealy dust. The sporophores are edible. 

The connection between the sporophores and the rhizomorph- 
strands was proved by Hartig. These rhizomorphs are very 
common and vary much in form ; they occur as round brown 
strands running through the earth from root to root of attacked 
trees ; inside hollow stems and in wooden water-pipes, they 
retain their rounded form, but under the bark of trees they 
become dark brown flattened bands (Fig. 288). They are not 
uncommon on timber ; in mines they may be frequently 
seen hanging from the woodwork as tangled clumps, with 

1 R. Hartig, Wichtige Krank/iei/en , PI. I. and II. ; Zersetzungserscheinungen, 
PI. XI. lie Bary, Botan. Zeitung, 1859. Brefeld, Sehim/melpilze, Heft, in., 1877. 


456 


I5ASIDI0MYCETES. 


numerous branches like the runners of some hanging plant, c.y. 
Aaron’s Heard (Saxifraga sarmentosa). The rhizomorphs live as 
saprophytes and have been long known to emit phosphorescent 
light. Sporophores are developed directly on them, and if one 
sows the spores, a delicate hyphal tissue is produced, which, 
under suitable conditions, passes gradually over into the rhizo- 
morph-strand. llrefeld succeeded in raising rhizomorphs from 
spores in artificial nutritive media. 



Flo. 285. — Agaricu* nulltu » near a Beech-stool, (v. Tubcuf phot.) 


The A f/arrctts-myceli um forms fan-shaped snowy-white firm 
membranous expansions under the bark of newly killed or still 
living trees. They are <piite distinct from the much more delicate 
mycelial expansions of Polyporu .s annosus, and offer a particularly 
easv means of distinguishing between the two species. Another 
indication of Ayaricux is the great outflow of resin from the bark 
at the base of the stem and from roots, whereby hard clumps of 
earth are formed round the roots. The passage of the rhizomorphs 
into the white membranous mycelium is easily observed. The 


AGARICUS. 


457 


rhizomorphs distribute the fungus in the earth and other dead 
substrata, as well as bore into the bark of healthy Conifers. 

This parasite attacks not only the indigenous Conifers (spruce, 
silver fir, pine, larch, and juniper ), 1 but also the introduced 
forms — Weymouth pine, Douglas fir, Pinus rigida, Abies Pichta , 
Picca sitchensis, various Cupressineae, etc. It also seems to attack 
broad-leafed trees, at least as a wound parasite . 2 

In regard to the interesting structure of the rhizomorphs, 
and the characteristic mode of wood-destruction caused by 



Fig. 286 . — Agaricux mrtlev.8. Sporophore 
developed from a rhizomorpli-strand ; the 
other branch bears arrested sporophores. 

(After R. Hartig.) 


Fig. 287. — Agaricus meUeus. Section 
through a lamella, d, The hyphae forming 
the substance of the lamella are much 
branched, and send twigs outwards which 
end in club-shaped basidia, a ; on many of 
these are developed sterigmata with apices 
swollen into spores, b ; c, isolated thread- 
like arrested basidia projecting above the 
hymenial layer. (After R. Hartig.) 



this fungus, I give directly the account by Hartig in his 

“Lehrbuch .” 3 “The pathological symptoms can only be ex- 

plained in the light of the peculiar organization of the mycelial 
growth that lives in the cortical tissues. The apex of the 

rhizomorphs consists of delicate pseudoparenchyma, which, 

elongating by the division and growth of the cells, produces 
delicate hyphae on the inside at a certain distance from the 

'I found it on juniper in the pine-forests near Eberswalde. (Auth.) 

2 The mycelium does not seem capable of penetrating uninjured broad-leaved 
trees, but R. Hartig (Forstl. -naturwiss. Zeitschrift , 1894, p. 428) mentions attack 
and death of cut roots of healthy oaks. 

3 R. Hartig, Lehrbuch d. Baumkrankheiten, 1889. The translation given 
here is from Prof. Somerville’s English edition of Hartig’s text-book, p. 
210. (Edit.) 


458 


BASIDIOMYCETES. 


point, whereby a felted tissue, called the medulla, is produced 
in the interior. The outer parts of the pseudoparenchyma, on 
the other hand, coalesce to form the so-called rind, which when 
young gives off numerous delicate hyphae, and these, taking 
advantage of the medullary rays, penetrate the wood, and 
especially the resin-ducts, should such be present. In the wood 
the growth is upwards. This filamentous mycelium, which pro- 
gresses much more rapidly in the interior of the wood than 
the rhizomorphs which grow in the cortex, completely destroys 



Fio. 288. Aporicu s uiellcu*. Rhizomorphs in the form of dark anastomosing 
Viands, developed between the bark and wood of a tree. (v. Tubeuf phot.) 


the parenchyma that exists in the neighbourhood of the resin- 
ducts, and to all appearance this is accompanied by a partial 
conversion of the cell-contents and the cell-walls into turpentine. 
The turpentine sinks down under its own weight, and in the 
collar, where the cortex is withered, having been killed by 
rhizomorphs, it streams outward, pouring partly in between the 
wood and the cortex, and partly into the surrounding soil at 
places where the cortex has ruptured owing to drying. On 
this account the disease was formerly called ‘ Itesin-flux ' or 


AGARICUS. 


459 


‘ Resin-glut.’ In the upper parts of the stem, where the cambium 
and cortex are still sound, the turpentine also flows laterally, 
by means of the ducts of the medullary rays, from the injured canals 
towards the cambium and cortex. In the. latter this accumulation 
induces the formation of large resin-blisters. When, during the 
summer, the cambium is forming a new ring, the plethora of 
resin has the effect of causing the production of numerous resin- 
canals, which are usually large and abnormally constructed, and 
these impart to the wood-ring formed during the year of sick- 
ness a very striking and characteristic appearance. 

“ The mycelium gradually spreads from the cells of the 
medullary rays and from the resin-ducts into the vascular 
elements of the wood, where it produces a form of decay which 
may be termed a variety of white-rot. During the progress of 
the decomposition from the surface of the stem inwards a certain 
stage is reached, which is highly favourable to the development 
of the mycelium. While previously it was simply filiform and 
furnished with numerous lateral hyphae, it now develops large 
bladder-like swellings, and at the same time the hyphae change 
into a kind of large-meshed parenchyma, which, like the tyloses 
in the vessels of many dicotyledonous trees, completely fills up 
the lumina of the tracheides. On account of the mycelium 
assuming a brown colour when in this condition, it makes the 
portion of diseased wood which it infests appear, to the naked 
eye, like a black line. As this kind of mycelium soon dies 
off and is dissolved, being replaced by a delicate filamentous 
mycelium, it seldom happens that the zone which it occupies 
exceeds the breadth of three to four tracheids. The walls of 
the elements of the wood afterwards display a cellulose 
reaction, and speedily dissolve from the lumen outwards. 

“ On account of the trees drying up, after the rhizomorphs 
have spread from the point of infection on the roots into the 
stem, and again from the stem into the hitherto sound roots, 
decomposition of the stem usually ceases before the mycelium 
has advanced from the alburnum into the duramen. It is only 
in the stool and roots that decay rapidly spreads throughout 
the whole of the wood.” 

Methods for exterminating this parasite are unknown, beyond 
removal of diseased plants and collection of sporophores. It 
would certainly be advisable not to plant young conifers on 


460 


BASIDIOM Y CETES. 


cleared forest-land where the fungus sporophores are numerous 
on dead stools or roots. 

Agaricus (Pholiota) adiposus Fr. 1 (Britain and U.S. 
America). This is a conspicuous bright yellow or honey-yellow 
toadstool, with a glistening slimy cap which, as well as the 
stalk, is beset with concentric darker scales (Fig. 289). The 
scales and delicate annulus become indistinct or disappear on 
old sporophores or after much rain. The stalk is thick, fleshy, 
and stiff, and while growing so changes its direction as to keep 
the cap always in a horizontal position. The pileus or cap, at 



Fig. 281*. — Agaricu* a/li/tona*. A, A mature and a very young sporophorc grown 
in the forest; the other sporophores were raised on Fir-wood in a cellar. The 
latter have longer thinner stalks, and a basal swelling beset with white down. 

/i, Mature and germinating spores, (v. Tubeuf del.) 

first globose, opens out cone-shaped or flat with a diameter of 
about 5 c.m. Remains of the velum adhere to the margin. The 
underside of the cap is at first yellow, later mouse-grey. 
The lamellae are of three sizes, the largest extending from 
margin to stalk. From the lamellae arise the basidia, with 
four sterigmata each giving off a single spore. The spores 
fall at maturity, and cover neighbouring objects with a brown 
dust. They are oval with a length of 7-1 0/* and a breadth 
of 5 -Gm- 

The sporophores spring up rapidly in large numbers on 

1 v. Tubeuf, “ Kine none Knmkheit <1. Weiasttmne.” Zt ilxrhr. f. Fort! ii. Jcujil 
wexen, IS!)0. 


AGARICUS. 


461 


living sterns of silver fir, beech, etc., and on felled wood . 1 In 
the forest, on newly erected piles of firewood, the yellow stools 
may frequently be found in every stage of development growing 
from the cut billets, while they are especially numerous on the 
rotting useless timber left lying. In cellars or other moist 




Fig. 290 . — Agaricus adiposus. Destruc- 
tion of Fir-wood. The deeply-corroded 
cross-fissures contain white mycelium ; the 
remainder of the wood is yellow, (v. 
Tubeuf phot.) 


Fig. 291. — Agaricus adiposus. Destruc- 
tion of Fir-wood. Later stage. The 
corroded fissures no longer contain my- 
celium. (v. Tubeuf phot.) 


chambers, the sporophores may be abundantly produced till 
Christmas, but out-of-doors, August is the time of fructification. 

The mycelium forms felted masses under the bark or in cracks 
of the wood, and thence the sporophores arise as little pale- 
yellow buttons, which gradually unfold and become differentiated 
into cap and stalk. While quite young, they show the darker 

1 Previous to the publication of v. Tubeuf’s investigation the fungus had only 
been observed on living beech and felled wood. 


462 


BASIDIOMYCETES. 


scales arranged regularly in concentric lines. The stools break 
out from living stems through cracks in the bark or from wounds, 

t •.(]. those made by wood-peckers. 

The fir-wood, normally white, assumes, 
when diseased, a yellow or honey-colour, 
more or less like the sporophore, while 
here and there, parts may become light 
brown. The hyphae grow in all direc- 
tions, but especially as white strands up 
and down the year-rings, while others 
in horizontal and vertical direction break- 
up the wood into irregular patches 
(Fig. 290). In the final stages of 
destruction the wood will be found 
laminated into its separate year-rings 
and very much broken up into irregular 
pieces (Fig. 291). 

The sporophores of this Agaricus are 
not uncommon protruding from bark- 
cankers caused by Accidiuvi elatinum, 
and its mycelium assists in the destruc- 
tion of the stem. 



Fig. 292.- Agaricim ndijmuvs 
and Poly poru* Hart I {fit. Destruc- 
tion of Fir-wood. The boundary 
of the regions affected by the 
two fungi is formed by a very 
dark line of demarkation. To 
the right the destruction is that 
produced by Polyporov# Harligii , 
to the left by Agaricus adipOMvs. 
(v. Tubeuf phot.) 


Agaricus (Pholiota) squarrosus (Mull.). On 
living and dead stems of broad-leaved trees. 
(Britain.) 

Ag. (Ph.) destruens (Brond. ). On living 
and dead stems of poplar. (Britain.) 

Ag. (Ph.) aurivellus (Batscli.). On living and dead stems of broad-leaved 
trees. (Britain.) 


“ FUNGI IMPERFECTI.” 

The fungi placed here have life- histories which as yet have 
not been completely investigated, most of them being known 
only in the form of pycnidia or conidia. The number of species 
was at one time much larger, but it is gradually being re- 
duced as the forms are proved to be stages in the life 
of some species of definite systematic position in the other 
groups already considered. 

The group may be divided into the provisional sub-groups, 
the Sphacropsuhar , Mdanconiiat , and Hj/phom yevtes. 


FUNGI IMPERFECTI. 


463 


I. SPHAEROPSIDEAE. 

Conidia abjointed from conidiophores contained in dark - 
coloured pycnidia somewhat spherical in form. The various 
species are provisionally arranged in genera according to the 
colour of the conidia and the number of cells contained in 
them. The families here included are the Sphaerioideae, Nec- 
trioideae, Leptostromaceae, and Excipulaceae. 

i. FAM. SPHAERIOIDEAE. 

Hyalosporae. 

Phyllosticta. 

Fungi with colourless spores, and producing sharply defined 
spots on living leaves. They occur on all kinds of woody plants, 
but as a rule the injury caused is too slight to be called a disease. 

From the long list given by Saccardo (Yols. III., ix., and x.) 
the following have been selected : 

Phyllosticta persicae Sacc. This produces on leaves of peach 
brownish-yellow spots, frequently marked by concentric zones. 
The name “ shot-hole fungus ” has sometimes been applied to 
this and other allied forms, because the leaves become more or 
less perforated by the withered spots falling out. The pycnidia 
on reaching maturity rupture the lower epidermis of the leaf 
in a star-like manner. Briosi and Cavara ■ do not regard this 
parasite as very harmful, because leaves attacked by it remain 
alive without serious prejudice to their function. 

Ph. pirina Sacc. has been observed injurious to pear-trees at 
Geisenheim (Germany). 

Ph. prunicola Sacc. is the cause of spotting of leaves of 
apple, plum, cherry, and apricot. (U.S. America .) 1 

Ph. cytisi I)esm. On leaves of Cytisus Laburnum in 
Britain and Europe. 

Ph. acericola Cook et Ellis. On various species of 
maple ( Acer dasycarpum, etc.). It is described by Galloway 2 

1 The chief authorities for the occurrence of the “Fungi imperfecti ” in 
Britain and North America are Massee (British Fungus Flora, 1895), Farlow 
and Seymour (Host-Index for U.S. America, 1891 ), and Saccardo (Sylloge 
fungorum). Professor J. W. H. Trail kindly revised the records for Britain. 
(Edit.) 

2 Galloway, “Report of sect, of Veget. Pathology for 1888.” U.S. A. Dept, 
of Agriculture, Washington. 


404 


FUNGI IMPEKFKCTI. 


as injurious, especially in nurseries and groves where the trees 
are grown in number. 

Ph. sphaeropsoidea E. et E. is another American species 
which has become prominent on account of its ravages in 
nurseries of horse-chestnut. The disease appears about the end 
of dune, and by August the foliage of attacked trees is almost 
entirely dead. 

Ph. grossulariae Sacc. On leaves of liibes Grossularia in Italy and North 
America. 

Ph. vulgaris Desin. A common species on leaves of species of Lonicera. 
(Britain and U.S. America.) 

Ph. sambuci Desm. On species of Sambucus. (Britain.) 

Ph. cornicola (D.C.). On leaves of species of Cornu* in America. 

Ph. limbalis Pers. On oblong white spots on leaves of box. (Britain.) 

Ph. tiliae Sacc. et Speg. On leaves of Txlia. (Britain.) 

Ph. maculiformis Sacc. is probably a stage of Sphaerella maculiformis 
Auersw. It is a dangerous parasite causing a leaf-spot on sweet chestnut 
(Caxtanea) and other trees. 

Ph. violae Desm. A source of considerable damage to violets in America ; 
it also occurs in Europe and Britain. 

Ph. althaeina Sacc. has been reported as dangerous to hollyhock in the 
United States. 1 

Ph. phaseolina Sacc. appears occasionally as a parasite on leaves of 
kidney beans. (U.S. America.) 

Ph. viciae (Lib.). On Vicia septum. (Britain.) 

Ph. cirsii Desm. On leaves of Cirsium. (Britain.) 

Ph. apii Hals. 1 produces a leaf-spot on celery, and has caused con- 
siderable loss in America. 

Ph. tabaci Pass, occurs on leaves of tobacco in Italy. 

Ph. bataticola Ell. et Mart., and others, have been recorded on sweet 
potato in America. 

Ph. betae Oud. occurs on leaves of sugar beet and mangel. 

Ph. tabifica Prill . 2 Prillieux believes the disease of beet- 
root known as “ heart-rot,” to be due to this Phyllostida. It is 
probably a conidial form of Sphacrdla tabijira Prill. The symp- 
toms of disease are withering of the outer leaves, followed by 
the appearance of whitish spots with withered tissue filled up 
with mycelium. Thence the disease spreads into the younger 
parts and causes “ heart-rot ” of the root. 

Frank is of opinion that “ heart-rot ” is caused by Sporides- 

1 .V. Atjric. Exper. Station It< port, ISSM. 

2 Prillieux ct Dclucroix, Hulk t. de In soc. mycol. <l> France, vn., 1891. 


PHYLLOSTICTA. 


465 


mium putrefaciens Fuck. This is probably the cause of the 
gradual blackening of the leaves, yet it does not appear to 
lose its saprophytic nature. 

Frank also gives Phoma betae Fr. as one cause of the heart- 
rot of the sugar beet (comp. Phoma). 

It will thus be seen that the cause of the rotting of beet- 
root, sugar beet, and mangold is still very obscure . 1 

Ph. galeopsidis Sacc. On leaves of Galeopsis Tetrahit. (Britain.) 

Ph. atriplicis Desm. On leaves of Chenopodium and A triplex in Europe 

and Britain. 

Ph. chenopodii Sacc. has been found injurious to spinach in America. 
Ph. podophylli (Curtis). In leaves of Podophyllum peltaturu in America. 
Ph. primulicola Desm. On withering leaves of Primula. (Britain.) 

Ph. ruscicola Dur. et Mont. On leaves of species of Ruscus. (Britain.) 


Depazea. 

A provisional genus including species of which the spores 
or conidia are unknown, so that the forms included in it will 
probably be found to be related to various groups. They live 
in many cases on living leaves, causing discoloration. Some 
of them are : 

Depazea acetosae Op. On Rumex Acetosa. 

D. impatientis Kirchn. On Impatiens Noli-tangere. 

D. geicola (Fries). On Geum urbanum. 


Phoma. 

Conidia unicellular and colourless. Pycnidia black and em- 
bedded, but having a distinct pore. The species produce spots 
with ill-defined margins. 

Phoma abietina Hartig 2 ( Fusicoccum abietimom Prill, et 
Delac). This parasite is a frequent cause of death to the 
silver fir. The branches become brown, yet retain their needles, 
hence when they occur isolated amongst neighbouring green 
branches they are at once conspicuous. On close examination 
of the dead or dying branches, areas of shrunk or eon- 

1 According to Karlson (Petrowsk. Akad. f. Landwirthscliaft, 1890) and Hell- 
riegel ( Zeitsch . des Verein f. Rubenzuckerindustrie d. deutsch. Reiches, 1890) 
insects take no part in it. 

2 Hartig, Lehrbuch d. Baumkrankheiten, Ed. n. (English Edition by W. 
Somerville). Mer, E. , Journal de Botanique, 1893. 


466 


FUNGI IMPERFECTI. 



stricted tissue will be found extending quite round the twig 
(Fig. 293). At these places the bark and cambium have been 

killed, whereas the higher 
portions of the twig have 
continued to increase in 
thickness. Numerous 
small black pycnidia 
break out on the bark 
of diseased places and 
give off small unicellular 
spindle-shaped conidia, 
which convey infection 
to new hosts in August 
or September. Killed 
branches die and dry 
up without casting their 
needles. 1 

Ph. pithya Sacc. 

causes a disease similar 
to the preceding on the 
Douglas fir (Pscudotsuga 
Douglasii). The pycnidia 
of the fungus are found 
on dead constricted parts 
of twigs, and they, as well 
as other symptoms of the 
disease, closely resemble 
those of Phoma abieiina . 
Rostrup 2 defined and de- 
scribed it as Ph. pithya 
Sacc. Magnus also re- 
cords it on branches of 

Fin. 2;13. — Phoma. abittin a. Twig of Silver Kir show- r, • ? . . • • ij i - 

ing the constriction characteristic of this disease, -* 1/1 K* Sl/I'l CSil US 111 fill 1111 
dotted over with pycnidia. (After R. Hartig.) botanic ‘UirdeU 

Other species of Phoma frequent other conifers and broad- 


t 1 Boh in (Ziitsrh. f. Forst- it. Jagd-toenen, 1800, p. 154) describes and figures 
an attack of this parasite on P-iendotsvga Douglanii in North Germany. One 
cannot, however, avoid suggesting some confusion between t his and Ph. pithya 
described next. (Edit.) 

- K. Rostrup Undersoegtlser over Suyltes rampes A ngrtb paa Skovtraeer, 
18S3-1888. 


PHOMA. 


467 


leaved trees, but details in regard to their parasitism are 
wanting. 

O 

Ph. Hennebergii Kuhn . 1 Brown-spot of wheat-ears. This 
produces, on the glumes of wheat, brown spots with projecting 
pycnidia from which unicellular conidia emerge. The grains of 
attacked ears shrivel up and become spotted, while the value 
of the chaff as fodder is much diminished. Whole fields may 
be attacked, showing marked discoloration, and producing but 
few healthy ears . 2 The fungus may also 
appear on the leaves and produce pycnidia. 

Ph. lophiostomoides Sacc . 3 Lopriore 
regards this as a parasite on cereals, but 
Cavara looks on it as saprophytic on the 
dead plants. 

Ph. ampelinum De Bary ( Sphaceloma 
ampelinum De Bary). Anthracnose of the 
Vine . 4 The mycelium of this fungus can 
penetrate into leaves, green bark, or fruit, 
and kills the tissues. Spots are first pro- 
duced, then enlargement of the neighbour- 
ing tissues takes place, causing the spots 
to appear as if sunk in depressions, and 
reminding one of hail-wounds. On leaves 
and grapes, the spots are sharply defined, Fig - 294 .— Pkoma ampeii- 

A ° % num. Brown concave spots 

at first dark-brown, later with o*reyish on shoot and berry of vit;s. 

® J (V. Tubeuf del.) 

centres and dark-brown margins. In the 

later stages the dried-up spots may drop out of the leaves. 

Anthracnose, or “ birds-eye rot,” constitutes one of the dreaded 
vine diseases of America and Europe, so that it has received 
much attention, both as to its life-history and remedial measures ; 
as yet however with but partial success. Copper sulphate 
solutions seem to be fairly successful remedies, as shown from 
results of the many experiments recorded in the Journal of 

1 Kuhn. Hedtoigia, 1877, p. 121; also in Rabenhorst’s Fungi europ. No. 2261. 
Frank, Zeitsch. fur Pfanzenkrankheiten, in., 1893, p. 28. 

2 Eriksson ( Mitthl . der k. Landb. Akad. Stockholm, 1890) records a case of 
this kind, but the conidia are drawn two-celled as in a Diplodina, whereas 
Kuhn’s original drawings have only one-celled conidia. 

3 Cavara et Eriksson, Zeitsch. f. Pfanzenkrankheiten, in., p. 23. 

4 Goethe, Mitthl. iib. den. schwarzen Brenner d. Reben. Leipzig, 1878. Cornu, 
Bullet, de la Soc. botan. de France, 1878. Prillieux (idem), 1879. Rathay, “ Der 
Black-rot," 1891. Scribner, Report of U.S. Amer. Dept, of Agricidlure, 1886. 



468 


FUNGI IMl’ERFECTI. 


Mycology and the bulletins and reports of the American experi- 
mental stations. (Compare also Gloeosnorium ampe/ophaoum 
(Pass.) p. 484.) 

Ph betae Frank. 1 The younger leaves of well-developed 
beet-root become black, and the disease extends into the root. 
Mycelium fills the diseased parts and penetrates into healthy 
tissues. Pycnidia are developed on the diseased spots. The 
fungus is no relation of Sporidesmium putrefaciens, a form to 
which a root-rot is ascribed by Frank. It is however probably 
identical with Prillieux’s Phyllostida todrifiea. Kruger found 
the disease so common, that in many localities as many as 80 per 
cent, of the plants were destroyed. Sorauer regards the root-rot 
of beet to be sometimes caused by Phoma, sometimes by 
Sporidesmium, perhaps in some cases by both together. 

Ph. sangninolenta ilostr. 2 attacks carrot plants in their first 
year, causing greyish-brown depressed spots on the bulbs with- 
out however appearing to be very injurious to them. When 
the seedlings are planted out in spring, the mycelium 
extends into the stem and causes the umbel to wither at 
flowering so that no seed is formed. Pycnidia are developed 
from all attacked spots and give off conidia as red tendril-like 
bodies — hence the species-name. Certain varieties of carrot 
appear to resist attack by this parasite better than others. 

Ph. solani Hals. This causes damage to the egg-plant 
( Solatium melon gena ). 2 Young plants die off on the hot-beds, 
their stems dying near the earth and shrivelling up. The 
pycnidia of this Phoma appear on the killed parts. 

Ph. cydoniae Sacc. has been reported as injurious to quince 
trees. (U.S. America.) 

' Many species cause leaf-spot diseases. Some of the more 
important British and American species are : 

Ph. pinastrella Sacc. On Pin us ttyl vestris and others. (Britain.) 

Ph. strobi (B. et Br.). On Pinu * Strobus. (Britain.) 

Ph. taxi (Berk.). On yew. (Britain.) 

Ph. Candollei (Berk, et Br.). On box. (Britain and U.S. America.) 

Ph. sorbi (Lasch.). On leaves of Pyrus Aucuparia. (Britain.) 

'Frank, Zeitxrh. J. I ‘Jtanzc idem nL'ht iten, III., p. 90, and Diufsr/n landia. Pr. 
No. SO, 1893. Kruger, Ztilsc/t. f. Pflan-cnkrankheiten, IV., 1894, ]>. 195. 

4 Described and figured by Halsted in Bulletin 91, X. J. A;/ric. Exptr. 
Station. 1892. 


PHOMA. 


469 


Ph. malvacearum West. On mallows and hollyhock in Europe. 

Ph. longissima (Pers.). In species of Umbelliferae and Chenopodiaceae 
in Europe and America. 

Ph. errabunda Desm. In stems of Verbascum. (Britain.) 

Ph. cucurbitacearum (Fr.). On fruits of various species of Cueur- 
bitaceae in Europe and America, 


Dendrophoma. 

Pycnidia similar to Phoma, conidiophores however bearing 
several conidia either on branches or little processes 

Dendrophoma Marconii Cav. attacks Hemp ( Cannabis sativa), 
causing dark oblong spots on the green stem. The pycnidia 
are embedded and break through the epidermis with a round 
pore. The conidiophores are branched, with swollen ends 
carrying little short rod-like unicellular conidia. In case of 
attack, which generally occurs towards the close of the 
vegetative period of the hemp, it is suggested to cut the 
crop somewhat prematurely, and thereby prevent maturing and 
spreading of the fungus. 

D. convallariae Cav. produces dark elongated spots on leaves of Con- 
vallaria mcijalis. 

D. valsispora Penz. is recorded by Penzig on living leaves of Citrus 
Limonum (Lemon). 


Sphaeronaema. 

Pycnidia embedded, membranous, and long-beaked. Conidia 
ovoid or oblong, unicellular, and almost colourless. 

Sphaeronaema fimbriatum (Ell. et Hals.), (Cn-atocystis 
fimbricda Ell. et Hals.). Black rot or black shank of sweet 
potato. 1 The parasite shows itself as black depressed spots on 
the lower parts of young plants, and these may extend over 
the whole shoot. The disease is best recognized on the tubers, 
where it consists of dark, somewhat greenish spots, varying 
from \ to 4 inches in diameter, and extending some distance 
into the tissue. These spots when once seen cannot be mis- 
taken, as they are sunk areas with distinct margins, like spots 
burned into the potato with a piece of metal which has left 
the skin uninjured. The mycelium consists of thick-walled 
olive-brown hyphae, which cause death and destruction to the 

1 Halsted and Fairchild, Jour, of Mycology, Yol. vii., 1891, with Figures. 


470 


FUNGI IMPERFECTI. 


cells of attacked tissues. There are three inodes of spore pro- 
duction : (1) brown macro-conidia inside the tissues; (2) colour- 
less micro-conidia on the spots ; (3) spherical pycnidia with long 
necks ending in a fringed opening. A sclerotial form is also 
strongly suspected. Remedial measures recommended are, de- 
struction of all diseased parts, change of crop on diseased fields, 
and selection of healthy seed and strong sprouts. 

Several other species of this genus are recorded from North 
America, but details in regard to their mode of life are 
wanting. 

Asteroma. 

Fungi forming star-like, dark-grey, mycelial patches on the 
surface of plants. Pycnidia very small and containing tiny 
ovoid or short cylindrical spores. Several species frequent 
living leaves. 1 

Asteroma impressum Fuck. On Tassilago farfara. 

A. prunellae Purt. On leaves of Prunella vulgaris. (Britain.) 

A. ulmi Klotscli. (Britain), and A. maculare Rud. On Ulmut. 

A. padi (D.C.) causes a leaf-fail on Prunut Padus. (Britain.) 

A. geographicum Desni. is found on the leaves of species of Crataegus. 
Prunus, and Pyrus in Europe and America. 


Pyrenochaeta. 

Pycnidia emergent or sessile, beset with bristles. Conidia 
oblong, on branched conidiophores. 

Pyrenochaeta rubi-idaei Caw forms black spots on leaves 
of Ruins Idacus. The pycnidia are spherical with a tuft of 
bristles projecting from their terminal pore. The conidia are 
little, oval, and with one or two cells ; they are produced from 
slightly branched conidiophores. 

Vermicularia. 

Conidia unicellular, rarely bicellular, generally spindle-shaped; 
they are produced inside pycnidia, and are embedded amongst 
brown septate hairs. The species are a frequent cause of leaf- 
spot, but most of them have not yet been sufficiently investigated. 

1 Cicinobuht.s Cesatii I)e Bury, allied to this genus, is a parasite on Oidiutn 
Tuckeri, the dreaded vine-parasite. 


VERMICULAKIA. 


471 


Vermicularia trichella Fr. occurs on living leaves of ivy and other plants. 
(Britain.) 

V. ipomoearum Schw. On species of Ipornoea in America. 

V. microchaeta Pasc. On living leaves of Camellia japonica in Italy. 
V. circinans Berk. Onion rot in Britain and U.S. America. 

Placosphaeria and Cytospora are genera containing forms 
parasitic on living plants, but of little practical importance. 


Phaeosporae. 

Coniothyrium. 

Pycnidia brown or black. Conidia brown, unicellular, spheroid 
or ovoid, and borne on short couidiophores. 

Coniothyrium (Phoma) diplodiella Sacc. 1 White-rot of the 
vine. This disease has a wide distribution in Hungary, and has 
also been observed in France, Italy, and America. It has caused 
considerable damage, especially in Northern Italy, where it was 
for a long time regarded as the black-rot. 

According to Mezey, this parasite is distinguished from 
Laestaclia (black-rot) in the following points The pycnidia 
and conidia are larger ; the mature pycnidia are greyish or 
light brown (never black), the mature conidia are brownish. 
The disease attacks the fruit only, causing it to fall off. Ihithay, 
however, states that it also attacks young shoots, infection taking 
place from the fruit. Diseased grapes become soft, rotten, and 
wrinkled ; the ridges are beset with pycnidial pustules, as in 
black-rot, but the grapes never become brittle and hard. 

Yiala and Eavaz 2 have recently succeeded in rearing perithecia 
from twigs and fruit-stalks set in sterilized moist sand. None 
could be found on grapes. The perithecia are globular, enclosed 
in a black covering several cells thick, and with a large crater- 
like aperture. The asci and paraphyses arise only from the depth 
of the perithecium, the latter being longer than the former and 
frequently branched. The asci are club-shaped and short-stalked, 
and contain eight spindle-shaped colourless or yellowish asco- 
spores, divided by one to three cross-septa. They germinate and 
produce one or more germ-tubes. 

1 Rathay, “ Der White-Rot,” Die Weinlaube, 1892. 

General description in Report 9, New York Afjric. Exper. Station, 1890. 

2 Yiala and Ravaz, Compt. rend., cxix., 1894, p. 443. 


472 


FUNGI IMPERFECTI. 


A new genus Charrinia, belonging to the Sphaeriaceae of the 
Ascomycetes, has been formed to receive this species. 

Sphaeropsis. 

Pycnidia black and spherical, with an aperture. Conidia ovoid 
or oblong, unicellular, dark-coloured, and on stalk-like conidio- 
phores. 

Sph. malorum Peck. The cause of a disease in America, 
known as the black-rot of apple and quince. The mycelium 
permeates and destroys the skin of the fruit, which, in con- 
sequence, becomes dried up and mummified. It also occurs in 
Britain. 

Other species attack plants of various Iiosaceae. 


Phaeodidymaf.. 

Diplodia. 

Pycnidia, small, spherical, and dark-coloured ; the conidia are 
two-celled when mature. 

Diplodia gongrogena Temme . 1 Temme discovered a mycelium 
and the pycnidia of this Diplodia in aspen ( Populus tremvlae ) 
exhibiting hypertrophied outgrowths of wood and rind. As yet 
it has not been possible to artificially produce these malformations 
on the aspen, nor other somewhat similar ones which occur on 
the willow. 

Other species of this genus attack many trees, c.g. holly, lilac, 
horse-chestnut, mulberry, and various conifers. 


Hyalodidymab. 

Ascochyta. 

Conidia ovoid or oblong, bicellular, and hyaline. The pycnidia 
have a central aperture, and are embedded in discoloured portions 
of leaves or twigs. 

The following species are of practical importance : 

Ascochyta pisi Lib. (Britain). Briosi and Cavara state that 

’Temme, Landwirth. Jnhrhurh, 1SS7. 

Thomas, Verhand. d. hot an. Vt rein d. Prov. Brandenburg, 1874. 


ASCOCHYTA. 


473 



this fungus is injurious to Pimm sativum, Phaseolus vulgaris, 
Vida sativa, etc. It causes spots on leaves and pods, followed by 
drying up of the former and deformation of the latter. The 
pycnidia appear as tiny points on the spots, and give out bieellular 
cylindrical conidia. 

As. Boltshauseri Sacc. 1 
This species was first observed 
in Switzerland on bean (Pha- 
seolus vulgaris). Leaves of all 
ages become brown -spotted, 
and premature defoliation may 
follow. The spots are marked 
by concentric zones, and bear 
pycnidia. The conidia are 
two- to three-celled, being 
distinguished in this and by 
their larger size from the 
preceding species. 

The following species fre- 
quent living leaves : 

Ascochyta tremulae Tliiim. On 
the aspen. 

A. metulispora, B. et Br. 

A. armoraciae Fuck. 

(Britain.) 

A. periclymeni Thiim. On Lonicera Periclymenum. 

A. maculans Fuck. On Hedera Helix. 

A. Ellisii Thliru. On Vitis Labrusca in America. 

A. brassicae Thiim. On Brassica oleracea. 

A. dianthi (A.S.). On Diantkus. (Britain.) 

A. pallor Berk. On Rubus Idaeus. (Britain.) 

A. viciae Trail. On Vicia sepiurn, etc. (Britain.) 

A. malvicola Sacc. On Malva sglvestris. (Britain.) 

A. graminicola Sacc. On various grasses. (Britain.) 

A. scabiosae Babh. On Knautia arvensis. 

A. nicotianae Pass. On JVicotiana Tabaccum. 

A. digitalis Fuck. On Digitalis purpurea. 

A. fragariae Sacc. has been found injurious to the strawberry crop in the 
United States. 

A. aspidistrae given (Gardener’s Chronicle, xvu., 1895) as a parasite on 
Aspidistra in Britain. 


Fig. 295 


Enlarged 


Ascochyta pisi on Pea. 
section of pycnidia, and still more enlarged 
conidia. (v. Tubeuf del.) 


On leaves of the ash in Scotland. 

On Armoracia rusticana (Horse-radish). 


1 Boltshauser-Amrisweil, Zeitschri/t f. Pflanzenkrankheiten, i., p. 135. 


474 


FUNGI IMl’ERFECTI. 


Actinonema. 

Pycnidia small and situated on a gossamer net of mycelium. 
Conidia hyaline and divided by one or more cross-septa. 

Actinonema rosae Lib. (Astcroma radiosum Fr.). This pro- 
duces black radiating spots on rose-leaves, on which pycnidia 
with bicellular conidia are developed. A premature defoliation 
takes place, which in turn causes the upper buds to unfold in 
autumn before their time. The mycelium is distributed both 
inside the leaves and superficially. Timely removal of diseased 
leaves and defoliated shoots might be recommended as remedial 
measures. 

A. tiliae Allesch. shows itself in spotting of the leaves and 
petioles of lime, and may bring about defoliation of the whole tree. 

A. fagicola Allesch. produces white spots with dark margins 
on living beech leaves, and causes gradual discoloration of the 
whole leaf. According to Allescher , 1 this disease brings about 
premature defoliation of beech. As yet it has been observed only 
in Upper Bavaria. 

A. fraxini Allesch. On living leaves of the ash. 

A. crataegi Pers. attacks leaves of Pyrus Aria, P. torminalis , anil 
Viburnum Opulus. 

A. podagrariae Allesch. On living leaves of Aegopodium Podagraria, 
and Chaerophyllum hirgutum. 


Darluca. 

Darluca genistalis (Fr.). On living leaves of Cytisiu sagittali .«. This may, 
however, he only a parasite on Uromyces cytisi with which it is frequently 
observed, just as Dar. filum occurs nil several Predincac. 

Diplodina. 

Similar to Diplodia, but having colourless conidia. 

D. castaneae Prill, et Delac.' produces canker-spots on the 
stems of chestnut, and brings about death. 

Phraomosporae. 

Hendersonia. 

Pycnidia formed under the host-epidermis, which is later 
ruptured. Conidia brown, two- or more-celled. 

1 Allescher, Htdwigia, 1894. 

2 l’rillieux et Delacroix, Hull. *oc. mycol. de France, 1S93. 


HENDERSONIA. 


475 


Hendersonia foliicola (Berk.) (Britain and Europe). The 
black globular pycnidia are produced superficially on leaves of 
Juniperus communis. The conidia are elliptical in shape, three- to 
five-celled, and abjointed from filamentous conidiophores. (This 
species is not identical with Podiosoma Juniperi ft minor Corda, 
which is more like the needle-frequenting form of G-ymno- 
sporanyium juniper inum .) 1 

Several species are found on living leaves : 

H. cydoniae C. et Ell. on quince in America. 

H. mali Tlium, on apple. 

H. rhododendri Tliiini, on Rhododendron hirsutum in Northern Italy and 
Germany. 


Cryptostictis. 

Similar to Hendersonia, but having ciliate spores. 

Cr. cynosbati (Fuck.). Sorauer 2 regards this as parasitic 
on Rosa canina, and causing death of portions of the rind. 

Stagonospora, Couturea, Asteromidium, and Camarosporium contain 
species said to frequent living leaves of various plants. 


ScOLECOSPORAE. 

Septoria. 

Spores generally multicellular and hyaline ; produced from 
short conidiophores, contained in lens-shaped embedded pycnidia. 

Septoria parasitica Hartig . 3 This disease may be frequently 
observed in young plantations and seed-beds of Spruce. The 
symptoms are very like those following damage by frost, brown 
needles appearing in May towards the base or middle parts of 
young shoots, and followed by a premature needle-cast. The 
disease is most apparent on lateral shoots, which become sharply 
bent downwards, the green needles hanging limply till they 
wither and fall as the whole shoot shrivels up. 

The pycnidia are little, black, and spherical ; they are pro- 
duced during the summer, particularly towards the lower end 

1 K. v. Tubeuf, “ Generatipms-wechsel Gymnosporangium-Arten,” Ceniralbl. f. 
Bakteriologie v. Parasitenkunde, 189). 

2 Handbuch d. PJlanzenkrankheiten, n., 1876, p. 388. 

3 R. Hartig, Zeitsch. f. Forst. u. Jagd-wesen, 1890; and Forstlich-naturwiss. 
Zeitsehrift, 1893. 


476 


FUNGI IMPKRFECTI. 


of the shoots, and either rupture the epidermis or grow out from 
the leaf-scar cushions (Fig. 297). The conidia are abjointed 
from filamentous conidiophores inside the pycnidia, and emerge 
as tendril-like structures. They are two-celled, small, cylindrical, 

and pointed at both ends. 
Germination takes place 
easily in water, and the 
disease spreads rapidly over 
the young developing shoots 
during May. The mycelium 
permeates the twig, living 
both inside the cells and 
between them. 

The disease has been 
observed on Picea excelsa 
and P. Mcnzicsii, not only 
in nurseries and on young 
trees, but also in pole- 
forest, where it frequents 
the upper crown and causes 
death. At the beginning 
of an attack the pruning 
of diseased twigs in young 
plantations should be at- 
tended to. 

Septoria rubi (Western!.). 1 Blackberry leaf-spot. This is a 
parasite of some economic importance in the United States, where 
it interferes with the blackberry culture. It also occurs in Europe 
and Britain. 

S. ribis Desm. produces a somewhat similar disease on leaves 
of currant and gooseberry. 2 (Britain and U.S. America.) 

S. piricola Desm. occurs throughout all Europe, causing little greyish 
spots tin leaves of pear trees. It is probably a pycnidial form of SphacrcUa 
lucillae Sacc. 

S crataegi Kich. A common species on leaves of Crataegus in Europe. 

S. cerasina Peck. On leaves of Primus scroti na in the United States. 

Many forms of Septoria infest cultivated vegetables : 

S. petroselini Desm. is the cause of dry spots appearing on leaves of 

1 Description in Bulletin, No. ti, Ohio Auric, k'r/icr. Station, ISStl. 

2 Description in Bulletin, No. 13, Iowa Auric. Ex per. Station, 1801. 


a 



Fio. 206 . — SrpLoria parasitica, a, Young diseased 
«hoot of Spruce, with apex still fresh and green. 
b, Needle diseased towards base, r, Apex of a two- 
year-old shoot, into which the disease lias extended 
backwards from the younger shoot; the brown 
discoloration of cortex and pith is indicated by 
shading. (After R. Hartig.) 


SEPTORIA. 


477 


cultivated parsley in Europe and Britain, 
enemy of celery in the United States. 

S. armoraciae Sacc. On 
horse-radish in America. 

S. consimilis Ell. et Mart, 
frequents lettuce in America. 

S. lycopersici Speg. This 
parasite, originally observed in 
America, has recently been de- 
scribed by Briosi and Cavara on 
tomatoes in Italy. It causes 
spots on leaves, stems, and 
fruits, inflicting thereby con- 
siderable loss on cultivators. 

The following are im- 
portant forms on other 
cultivated plants : 

S. graminum Desm. 
causes light spots on leaves 
of wheat, oats, and grasses. 

It has been observed to 
injure the cereal crop in 
Italy . 1 2 It is recorded for 
Britain and U.S. America. 

S. cannabis (Lasch.). 

This on leaves of hemp pro- 
duces spots, which are at 
first whitish, then yellowish 
with dark margins. The 
pycnidia are embedded in 
the upper side of the leaf. 

The following species 
have caused injury to 
garden plants : 

S. dianthi Desm. Car- 
nation-spot." The disease 
appears on the leaves and 
stems as rounded spots of 


A variety (apii Br. et Cav.) is an 


a 



1 Cavara {Zeitsch. f. Pflame.nkrarikhe.iten, m., p. 23) regards this and S. tritici 
with its varieties, as forms of a single species ; also Eriksson ( Om Ndgra 
sjukclomar a odlade Vaxter, 1890). 

2 Atkinson, “ Carnation Diseases,” at American Carnation Society, 1893. 


478 


FUNGI IMPERFECTI. 


dirty white or brownish colour with a darker margin. The 
pycnidia appear as black points on the spots, and rupture the 
epidermis before giving off their septate spores. 

S. anemones Desm. On Anemone. (Britain.) 

S. lychnidis Desm. On Lychnis diurna. (Britain.) 

S. epilobii West. On Epilobiv.rn. (Britain.) 

S. stachydis D. et R. On Stachys. (Britain.) 

S. urticae L). et R. On Urtica dioica. (Britain.) 

S. cyclaminis Dur. et Mont. This produces roundish spots with 
concentric markings on the leaves of Cyclamen which then gradually 
wither. 

S. chrysanthemi Cav. causes a leaf-spot on Chrysanthemum japonicum and 
C. indicum. 

S. exotica Speg. attacks cultivated New Zealand species of Veronica. 

S. hydrangeae Bizz. causes injury to cultivated Hydrangea. 

S. sedi West, injures Sedum under cultivation in the United States 
and Britain. 

Other species on many other herbs in Britain and America. 

Many species of Septoria have been recorded on trees and 
shrubs, e.g . : 

S. rosae Desm. On roses. (Britain.) 

S. hederae West. On ivy. (Britain.) 

S. fraxini Desm. On the ash. (Britain.) 

S. nigro-maculans Thum. On green walnuts, stunting their growth. 

S. castaneae Lev. On the sweet chestnut. 

S. aesculi (Lib.). On the horse chestnut. (Britain.) 

S. pseudoplatani Rob. et Desm. On leaves of sycamore. 

S. populi Desm. On leaves of poplar. 

S. didyma Fuck. On Salic triandra and S. alba. 

S. cornicola Desm. On leaves of Cornu s sanguinea. 


Phleospora. 

True pycnidia arc not formed, but the conidia are alijointed 
from cavities in the stroma ; they are hyaline, rod- or spindle- 
shaped, and consist of two or more cells. 

Phleospora aceris (Lib.). On living leaves of .leer Pseudoplatanus. 
(Britain.) 

Phi. mori (Lev.). On living mulberry leaves ; probably related to 
Sphaerella mori. (Britain.) 

Phi. ulmi (Fr.). On living leaves of elm. (Britain and America.) 

Phi. oxyacanthae (K. et S.). On living leaves of Crataegus Oxyacantha. 
(Britain.) 


DILOPHOSPORA. 


479 


Dilophospora. 

Dilophospora graminis Desm. (Britain.) This attacks rye, 
wheat, and various grasses. Oblong light spots are produced 
and bear the pycnidia ; when these occur in the flower heads, 
stunting of the grain takes place. (See also Dilophia, p. 222.) 


2. FAM. NECTROIDEAE. 

The fungi of this family are chiefly pycnidial forms of the 
Ascomycetes, and as such have already been considered. 


3. FAM. LEPTOSTROMACEAE. 

Hyalosporae. 

Leptothyrium. 

Pycnidia black and discoid. Spores ovoid or spindle-shaped, 
unicellular, and hyaline. 

Leptothyrium periclymeni (Desm.). On living leaves of 
species of Lonicera. (Britain.) 

L. alneum (Lev.) produces roundish leaf-spots on species of 
Alnus. (Britain and America.) 

L. acerinum (Kunze) causes spotting of the leaves of Acer 
campestrc and A. platanoides. (Britain.) 

Several other species occur both in Europe and America. 


Melasmia. 

The black pycnidia occupy black extended stromata. Conidia 
simple and unicellular, borne on rod-like conidiophores. 

Melasmia berberidis Thum. et. Wint. On living leaves 
of barberry. Brown spots are produced, bearing the pycnidia 
as black points ; the spots cause total or partial death of the 
leaves, frequently ending in defoliation of the shrubs. 

M. empetri Magn. (Britain.) This species was observed by 
Magnus 1 causing an epidemic disease on crow^berry. The 
symptoms were abnormal elongation of young twigs, and the 
leaves remained smaller than usual. The rind of the stem was 
found to be permeated by a mycelium which produced black 

1 Berichte d. deutsch. botan. Gesell., 18S6. With illustrations. 


480 


FUNGI IMPERFECT I. 


pustules bearing the pycnidia of this Melasmia. The cells of 
the cortex dried up, and the rind became detached from the wood 
in the following year. The leaves were never found attacked. 
(The species is not a Rhytisma ; nor does any species of Rhytisma 
produce similar hypertrophy of its host.) 

M. acerina. M. punctata, and M. salicina are now recognized only as 
pycnidia of the species of Rhytisma bearing these same specific names. 


Leptostroma. 

Pycnidia oblong, black, and flattened. Conidia ovoid or 
oblong, unicellular, and whitish. 

Leptostroma punctiforme Wallr. Found on the leaves of 

Salix, Rosa, Buxus, Euphorbia, etc. 

L. caricinum Fr. frequents leaves of Carex and Eriophorum 
in Europe and North America. 

The parasitism of other species is uncertain. 

Labrella and Discosia are genera whose species have not as yet pro- 
duced diseases of any serious economic importance. 


Phragmospoka e. 

Entomosporium. 

Entomosporium maculatum (D.C.) Lev . 1 This fungus, under 
the name of leaf-blight of pear and quince, is the cause of 
considerable loss in the cultivation of these crops. Defoliation 
takes place early in the season and young seedlings are forced 
to form a new set of leaves, whereby their reserves of food are 
exhausted. If this be repeated several times the plants become 
exhausted and are killed off in winter. Stocks already budded 
seem to remain immune if not already diseased. The leaves 
are first attacked, but later the succulent growing apex of the 
twigs may also succumb. The parasite hibernates on the bark 
in small depressions containing the pycnidia; thence it spreads 
in early spring, so that pustules appear on the young leaves 
before they are fully developed. 

Spraying with Bordeaux mixture, or solution of copper acetate 

'Galloway and Southworth {Report for 1888 of Section of Vajctahh Patholoijy, 
Dept, of Agriculture, U.S. America) give a historical account of the fungus 
and a bibliography. (Edit.) 


ENTOMOSPORIUM. 


481 


(6 oz. in 26 galls, water) have both produced good results in 
checking the disease. 1 

E. mespili (D.C.). (See Stigmatea mespili, p. 210.) 


SCOLECOSPORAE. 

Brunchorstia. 

Brunchorstia destruens Erikss. (B. joini Allesch.). In Nor- 
way almost all the plantations of Austrian black pine ( Finns 
Laricio ) from five to thirty years old have become diseased and 
died out. Similar ravages have also been observed in Germany. 
Brunchorst ascribes this to a parasitic fungus whose mycelium 
may be found in all parts of diseased twigs and needles, and 
whose pycnidia are formed on the killed remains. The disease 
begins in young first-year twigs, the mycelium growing in 
the cortex, pith, and wood. The needles are attacked in 
summer, become brown from the base upwards, and the 
pycnidia make their appearance under the scale-leaves. 

Brunchorst 2 describes the fungug as follows : Pycnidia par- 
tially embedded in the tissues of the host-plant ; the smaller 
ones being simple, the larger divided by complete or partial 
partitions. The inner wall as well as the partitions of the 
pycnidium are closely beset with straight basidia, from the 
apices of which stylospores with two to five septa are abjointed. 
Paraphyses are never present. The perithecia are black, oblong 
or rounded, slightly grooved, and 1-2 mm. in diameter; they 
dehisce by one or more irregular pores in the wall. The 
spores are very minute (30 — 40 — 3/x), tapering, and rounded 
at each end. 

Schwarz considers Brunchorstia as a conidial form of Cenan- 
guim abictis already described (p. 251). 

It may be here mentioned that drying-up of pine-twigs may 
be due to heating by the sun in frosty weather, or to frost 
itself ; 3 these are, however, quite distinct from the disease just 
described. 

'Fairchild (Journal of Mycology, Vol. vii. ) gives results of treatment with 
various fungicides on several varieties of pear and quince. (Edit.) 

2 “Ueber eine neue Krankheit d. Schwarzfohre.” Bergens Museum, 1889. 

3 R. Hartig, “ Vertrocknen u. Erfrieren d. Kiefernzweige,” Forstlichnaturwixs. 
Zeitschrift, 1892 and 1895. 


482 


FUNGI IMPERFECTI. 


4. FAM. EXCIPULACEAE. 

The parasitic nature of the species of this family has not as 
yet been investigated to any extent. 


II. M ELAN CONIEAE. 

True pycnidia are not formed, but the conidia are developed 
in clusters or aggregations covered over at first by the epi- 
dermis of the host-plant, which is ultimately ruptured. 


Hyalosporae. 

Gloeosporium. 

Conidial clusters colourless or grey, never black ; they rup- 
ture the overlying epidermis and give off unicellular conidia, 
one from each conidiophore. 

Gloeosporium fructigenum Berk . 1 (Britain and U.S. America). 
Apple Bot or Bipe-rot. This is a very serious disease for 
American cultivators. It not only attacks apple, but also the 
grape, pears, peaches, and egg-plants . 2 On the apple it appears 
first as brown spots which become more conspicuous as the 
fruit enlarges. The spots on first sight look like decay, but 
they are quite firm and soon bear pustules of a white or 
pinkish colour turning to black. The attacked part of the apple 
has an intensely bitter taste, and should be carefully removed 
before eating the fruit. On grapes the fungus produces tiny 
raised pustules, which on the white varieties are situated on 
spots with a purple centre and a brown margin ; the pustules 
when mature give off flesh-coloured conidia. The grapes 
gradually shrivel up, but do not become black as in the case 
of the black-rot, nor do they assume a bitter taste as the 
apples do. 

The apple bitter-rot makes rapid progress amongst stored 
fruit, especially before it has been sorted out. Care should 
therefore be taken that diseased apples are removed as soon 
as possible. 

The spraying of trees bearing young fruit with copper ear- 

1 South worth, Journal of Mycology, vi., p. 164. 

2 Hals ted, Bulletin of the Torn;/ Club , 1893, p. 109. 

Massee, Gardener's Chronicle, Vol. xrv., 1S93. 


GLOEOSPORIUM. 


483 


bonate or potassium sulphide solutions has good effects on the 
yield of the orchards. In vineyards under treatment for black- 
rot or mildew, there is little chance of the ripe-rot fungus 
appearing. 

It is probable that the species known as Gl. phomoides 
Sacc. on tomato, Gl. piperatum E. et E. on peppers ( Capsicum 
annuum), and Gl. melangeae E. et Hals, on the egg-plant, are 
identical with Gl. fmctigenum. At least they very much 
resemble each other, even on their widely differing substrata, 
and cross-infections have been carried out. 

Gl. venetum Speg. (Gl. nccator Ell. et Ev.) Anthracnose of 
raspberry and blackberry . 1 This disease appears on both canes 
and leaves. On the young shoots it produces small reddish- 
purple spots during early summer ; as the season advances the 
spots run together into irregular blotches of more or less 
greyish colour with a dark purple margin. The ripening fruit 
remains small and shrivels up. Leaves may also bear spots, 
but they more frequently remain smaller and have an unhealthy 
look. The conidia are at first enveloped in a thin covering, 
which becomes gelatinous when wet, so that they escape. The 
mycelium is believed to perennate in stems or decayed remains, 
and so to carry the parasite from season to season. Owing 
to the delicate nature of raspberry foliage, fungicides must be 
used with great care. Dilute Bordeaux mixture is said to be 
safe and beneficial. The burning of diseased canes should 
certainly be carried out each autumn. 

Gl. ribis (Lib.). This attacks currant bushes throughout 
Europe and America in much the same way as Gl. venetum. 
The leaves wither and fall, so that the fruit-crop suffers. 
(Britain.) 

Gl. amygdalinum Brizi . 2 This has recently been described 
as destructive to almond cultivation in Italy. The mycelium 
inhabits twigs and fruits, and gives off tufts of conidiophores 
bearing conidia ; as a result, wounds are produced in the 
epidermis and stunting of the host-tissues takes place. 

Gl. rosae Hals, is described as injurious to rose-culture in 
America. It may be identical with some of the species of 
Gloeosporiuvi already mentioned as frequenting Bosaceae. 

1 U.S. A merica Dept, of Agriculture, Report for 1889, contains a good account. 

2 Brizi, Zeitsch. f. Pfanzenkrankheiten, 1896, p. 65. 


484 


FUNGI IMPKRFECTI. 


Gl. ampelophagaim (Pass.) 1 Black-rot of the vine. This 
disease is very injurious and has a wide distribution in Europe. 
It is known under many names such as “ Bock, Brand, Host, 
Jausch, Brussone, and Xebbia nera,” though probably these 
names include several distinct diseases. The identity of this 
Gloeosporivm is somewhat uncertain, and it may really be 
identical with Phoma ampelinum (p. 467). Bathay ascribes the 
black rot to Sphaceloma (Phoma) ampelinum, while Thiimen 
regards Gloeosporivm as the cause. Briosi and Cavara consider 
the two species of fungi as distinct. Thiimen says that the 
patches of Gloeosporivm are for a considerable time disc-like 
and of a light-grey rose colour ; those of Phoma, on the other 
hand, are always depressed and brown. B;ithay, however, de- 
scribes the spots of Phoma as at first dark brown, and later 
ashy grey with a brown margin. 

The spots appear on green parts of the vines during April 
and May. Those on the leaves frequently fall out, leaving 
holes. On the grapes the spots are smaller and produce a 
brown coloration extending deep into the fruit. The conidia 
are small, hyaline, oval, and unicellular; they are abjointed 
from very short conidiophores arranged in little clusters. The 
conidial patches rupture the host-epidermis, and the conidia are 
liberated. 

Thiimen suggests that the soil of vineyards should be kept 
well cleaned, and that the stake mode of culture be used in pre- 
ference to an overhead trellis ; he also recommends the washing 
of all parts of suspected vines during winter with 10 to 15 
per cent, solution of sulphate of iron. This treatment is said 
to have been very beneficial in keeping many vineyards quite 
healthy and free from fungi. 

Gl. nervisequium." This parasite occurs on species of PI at anus 
in Europe and America. Brown spots appear on the leaves, 
especially on the veins ; these as they extend cause sudden 
withering and fall of the leaves. Pustules containing a stroma 
develop on the spots, and unicellular, ovoid, hyaline conidia are 
abjointed from club-shaped conidiophores. 

'Thiimen, Die Poeken an IFetn u. Oi>u. 1885: Die liekiimpfung <1. Pihkravk- 
heilen, 18S6; l)e Bary, Anna/en il. Oenologie, iv. ; Viala, Lex maladies dt la Vignt ; 
Briosi e Cavara, F might /taraxit., hi.; 15 . Riitlmy, “ Der /{/ark- Hot," 18511. 

2 U. S. Ameriea Department of Vegetable Pathology, Report for 1888, gives a 
general account of this disease. 


GLOEOSPORIUM. 


485 


Several fungi of very near relationship, if not actually identical, 
occur on Platanus. 1 All cause considerable disfiguration of the 
foliage, so that a systematic destruction of all young diseased 
branches is strongly recommended. 

Gl. cingulatum Atks. 2 This is the cause of Anthracnose on 
Privet ( Ligustrum vulgare ) in the United States. The following 
is Atkinson’s diagnosis : “ Affected areas light brown, either 

oblong on one side of the stem or completely girding it. Aeer- 
vuli 100 to 150 in diameter, rupturing the epidermis, in age 
black from the dark stroma lying in the base or extending 
irregularly up the sides, frequently forming a pseudopycnidium. 
Basidia numerous, crowded, simple, hyaline, or when very old 
perhaps faintly fuliginous. Spores oblong, or elliptical, straight 
or little curved, usually pointed at the base. From pustules 
on the stem they measure 10-20 by 5-7 ; in artificial cultures 
they are frequently much larger, but when crowded in the media, 
or when the nutrient substances are nearly exhausted, they may 
be considerably smaller. On stems of Ligustrum vulgare. 

“ This is quite distinct from Gloeosporium ligustrinum Sacc.” 

Many species of Gloeosporium frequent broad-leaved trees 
and cause more or less injury to the foliage. 

Gl. rhododendri Br. et Cav. attacks the leaves of outdoor 
cultivated rhododendrons in autumn, or indoor species in 
winter. Large yellow spots marked with concentric zones 
are formed, and bear the pycnidia ; finally the leaves dry up 
and fall off. 

Gl. violae B. et Br. attacks violets in Britain and U.S. 
America. 

Gl. vanillae Cke. et Mass. ( Calospora vanillae Massee. 3 ) 
This causes a dangerous disease on Vanilla planifolia and other 
Orchideae in Mauritius and other parts of the tropics. Death 
is brought about by the Gloeosporium ( Hainsea ) form of the 
fungus, the higher reproductive organs only appearing when the 
leaves are killed. 

Other species are known, but their economic importance is not 
great. 

1 v. Tavel, Botan. Zeitung, 1SS6 ; Leclerc du Sablon, Revue gen. <le Botanique , 

1892. 

2 Atkinson, “A New Anthracnose of the Privet,” Cornell Univ. Agric. Exper. 
Station Bulletin, No. 49, 1892. 

3 Massee, Kew Bulletin, 1892, p. 111. 


486 


FUNGI IMPERFECTI. 


Myxosporium. 

Conidia ovoid, hyaline, and abjointed from rod-shaped basidia 
situated in cavities of the cortical tissues of arboreous plants : 
a true pycnidium is not formed, and the reproductive mycelium is 
only covered over by the epidermal layers of the host. 

Myxosporium devastans Postr. 1 is said to attack and kill 
young twigs of Betula verrucosa. The conidial patches are 
developed in the killed rind, and give off unicellular colourless 
conidia. 

M carneum Lib. is parasitic on twigs of beech. 

M laneola Sacc. et Rourn. causes deatli of oak-twigs. 

The other known species have as yet been observed only as saprophytes. 


Colletotrichum. 

Conidial patches surrounded by setae ; characters very like 

Glocosporium. 

Colletotrichum Lindemuthianum (Sacc. et Magn.). J This 
disease, first observed by Lindemuth in 1875, has assumed 
great importance as a disease of the kidney bean {Phascolus 
vulgaris) both in Europe and America. Young pods are most 
frequently attacked, but neither stems nor leaves are exempt. 
The pods show brown depressed spots with a distinct margin. 
The unicellular and oblong conidia are given off from short 
conidiophores developed on the spots. Germination takes place 
at once, the germ-tube forming an adhesion-disc on the host- 
epidermis, and from this a hypha penetrates into the tissues 
to develop into a brown mycelium. Frank obtained brown 
spots and mycelium on young beaus twenty-four hours after 
infection. 

C Lagenarium (Pass.) (C. oligocluv turn Cav.). This parasite 
is very injurious to seedlings of water melon (Cucmnis citrullvs), 
melon ( C . Milo), and the gourd (C it curin' fa Layenaria). Leaves 
and fruits may be attacked, but it is the cotyledons and stems 
of the seedling plants which most frequently fall a prey. Spots 

1 Rostrup, Tids*krift f. SLorracxeyi, 1 893. 

- For the relationship of this with the following species, as well as their 
synonomy. see Halsted in Bulletin of Torn y Botanical Club , 1893, p. 246. 
Description, treatment, and bibliography by Reach, “ Bean -spot disease,” Centra 
_Y. )'. Exper. Station Bulletin, No. 48. 


COLLETOTRICHUM. 


487 


appear on the leaves, and depressions on the stem, sometimes 
extending so far round that the whole shoot dries up. The 
conidial patches are very much the same on the different hosts, 
and consist of short conidiophores from 
which oval, unicellular, hyaline conidia 
are ab jointed. 

C. lycopersici Chest, is the cause of 
a spot-disease on the fruit of tomato in 
the United States. 

C. spinaciae Ell. et. Hals, causes a 
destructive disease on cultivated spinach. 

C. malvarum Br. et Casp. ( C . altliaeae 
Southw. 1 ) produces a disease of cultivated 
hollyhock. It is most injurious to the 
seedling plants, and has caused great 
loss in America and Sweden. The fungus 
may attack any organ, and produces spots 
which enlarge so rapidly that death of the 
host may result. 

C. gossypii Southw . 2 Anthracnose of 
Cotton. This disease, although it may 
be found on stems and leaves, is most 
frequent and most conspicuous on the 
fruits or “ bolls ” of the cotton-plant. 

The first signs are tiny depressed spots 
of a reddish-brown colour, and as these 
enlarge they cause blackening of neigh- 
bouring tissue. When the spores are developed the spots 
become dirty grey, or perhaps pinkish if the spores are present 
in large numbers. Fruit attacked in this way does not mature 
well, and the yield of cotton is greatly prejudiced. Atkinson 
found the cotyledons easy to infect with the disease. The 
spores are oblong and tapering, with a shallow constriction in 
the middle ; they are borne either on short colourless basidia 
or on long, olive-coloured, septate setae, both kinds of conidio- 
phore being produced in acervuli or patches. 

C. adustum Ell. is the cause of a leaf-spot on orange in Florida. 



Fig. 298. — Colletotrichura Linde- 
muthianum on pod of Kidney 
Bean. Enlarged pustule and 
conidia. 


1 Southworth, “A New Hollyhock Disease,” Journal of Mycology, vi., 1890. 
2 Southworth, Journal of Mycology, vi., 1890, p. 100. 

Atkinson, Alabama Agric. Exper. Station Bulletin, No. 41, 1892. 


488 


FUNGI IMPERFECT!. 


Faded spots appear on the leaves, becoming later greyish brown dotted 
over with minute black points, the conidial patches . 1 

C. ampelinum Cav. causes little dry spots on the leaves of vine, fre- 
quently in such numbers that the whole leaf dries up. 

C. kentiae Hals, attacks palm-seedlings so 
that their leaves do not unfold. 

C. cyclameneae Hals, occurs on Cyclamen. 

Scoleco-Allantosporae. 

Cylindrosporium. 

The white and shining conidial 
cushions are embedded in the host- 
plants. The conidia are filamentous, 
frequently somewhat twisted. 

Cylindrosporium Tubeufianum Alles- 
cher. This attacks the living green fruit 
of the bird-cherry, and causes the forma- 
tion of brown spots from which pustules 
break out ; the premature dropping of 
diseased fruits follows. In the locality 
where I observed this disease, numerous 
trees were attacked and most of the fruit 
on each was badly diseased. The my- 
celium spreads through epicarp and 
mesocarp, but does not penetrate into 
the endocarp, so that the development 
of the embryo is not directly interfered 
with. The conidia originate in pycnidial 
cavities without any special peridium ; 
their shape is given in the annexed 
diagnosis . 2 The pycnidial cavities arise 
under the epidermis which is afterwards ruptured and with t lie 
cells underlying it becomes brown and dead. 

'This note is taken from Underwood, Journal of Mycology, vn .but no 
mention is made of it in the later paper by Webber and Swingle (“ Diseases of 
Citrous Fruits in Florida,” U.S.A. Dept, of Agricult tin Bulletin, 8, 1896). (Kdit.) 

2 Allescher gives the following diagnosis of this species: Piutnlin primutn 
convexis, epicarpio tecti dein applanatix xcutifonnibuxre, epicarpio rtipto cinctix, 
tmbcircularibux, xaepr caesjiitosi* nl confluent Unix, luteo-brunneolix, snbfnrfiintct is ; 
acerntlis, min lit in, iunatix, erunipentibux : conitliis fllifonnibns, rurratix rel flex- 
nosix multiyuttulatix, hyedinix 40-60 2-.'V. /fab. in fructibu > immaturis I'rnni 
Cadi, quox necat. 



Flo. 209. — Cylindrosporium 
Tubtufianum on fruitH of Prunu* 
Patlu*. The unshaded parts re- 
present parts still green and 
living, although l>earing pustules 
here and there ; the remaining 
parts arc completely beset by 
pustules, so that the cells are 
killed and brown. J natural 
size. (v. Tubeuf del.) 


CYLINDROSPORIUM. 


489 


As yet the disease has been observed in quantity only in 
the neighbourhood of Oberammergau (Upper Bavaria). 

C. padi Karst. Leaf-blight of cherry and plum. This dis- 
ease is most destructive in the nursery, causing premature 
defoliation of young trees ; it may also cause severe injury to 
fruit-bearing trees. The leaves become spotted and perforated 
by holes caused by the falling out of withered spots. Spraying 
with dilute Bordeaux mixture early in the season is said to 
have good effects. 1 



Fio. 300. — A fruit from Fig. 299 (enlarged). A, Two pustules still further 
enlarged. B, Pustules before and after rupture of the epidermis. C , Isolated 
conidia. (v. Tubeuf del.) 

C. filipendulae Tliiim. occurs on leaves of Spiraea Filipenclula, 

C. ficariae Berk. On leaves of Ranunculus Ficaria. (Britain.) 

C. viridis E. et E., and C. minus E. et E. On leaves of Fraxinus viridis 
in the United States. 

C. cercosporoides E. et E. On living leaves of tulip-tree. 

C. saccharinum E. et E. On living leaves of Acer saccharinum in the 
United States. 


Cryptosporium. 

Conidial cushions shaped like pycnidia. Conidia rod-like or 
spindle-shaped. 

Cryptosporium leptostromiforme Kuhn.' 2 This fungus forms 
rows of black stromata on the stems of lupines; in the stromata 
are formed pycnidia-like cavities with several neck-like openings, 
and in them conidia are given off from conidiophores. The 
conidia are rods with rounded ends 7-8'op long and about 
2 n broad ; they emerge from the necks of the cavities as 
long tendril-like chains, and may be continuously given off 

1 Fairchild ( Journal of il fycoloc/y, vii., p. 240) gives results of remedial 
treatment. 

2 J. Kuhn, Berichte d. landwirth. Inst.., Halle, 1S80. 

Fischer, “ Cryptosporium leptostromiforme.” Breslau, ISOS. 


490 


FUNGI IMPERFECTI. 


throughout the whole summer. Fischer has proved experi- 
mentally that the conidia germinate easily in water, that the 
germ-tubes penetrate into living lupines, and produce a mycelium 
which spreads through stems and leaves to develop stromata on 
all the organs of the plant. The formation of both pycnidia and 
conidia goes on throughout the autumn and following spring on 
dead plants, the fungus being capable of living as a saprophyte 
and of hibernating. The disease may occur with great severity. 
Fischer describes cases where more than the half of the plants in 
a field were attacked and died before flowering or soon after. 
There is thus a loss not only in lupine seed, but also in the good 
effects which the crop has as a “ green manure.” 

Fischer gives the following measures for keeping this pest 
in check : “ Where the fungus has obtained a footing, lupines 
should not be planted till at least the year after next, and then 
only as a catch-crop on stubble ; it would be still safer to keep 
lupines off the land till the third or fourth year. After lupines 
as a catch-crop, they may safely be sown again in spring as a 
seed crop, after the lapse of a clear year. Xo lupines should 
be cultivated near diseased fields. Instead of ploughing-in a 
catch-crop of lupines directly, it should be dried and used as 
litter for cattle, because the excrement has been found to kill 
the fungus; the lupines after lying over winter in the manure- 
heap could then be used as manure in spring. Similarly when 
the lupines have been grown for seed, they should be closely 
mowed down so that little stubble is left ; the straw may then 
be used for litter.” 

This fungus has not as yet been observed on plants other than 
lupines. 

I )I OYMOSrOHAK. 

Didymosporium. 

Conidia brown, oval or spindle-shaped, bicellular, and not 
produced in chains. 

Didymosporium salicinum Vuill. Yuilleuiin reports this as 
very destructive to the Osier cultivation in llourgogne. 

Marsonia. 

Conidia transparent, two-celled, and not produced in chains. 
The species live on leaves. 


MARSONIA. 


491 


Marsonia juglandis (Lib.) produces on leaves of Juglans little 
greyish yellow spots with brown margins ; thereon stromata are 
formed, which rupture the epidermis and liberate the large sickle- 
shaped conidia. (Britain.) 

M. populi (Lib.). On leaves of species of Populus in Europe and Britain. 

M. potentillae (Desm.). On species of Potentilla. (Britain.) 

M. campanulae Bres. et All. On Campanula latifolia. 

The following are North American species : 

M. toxicodendri (Ell. et Mart.). On Rhus Toxicodendron. 

M. quercus Peck. On Quercus ilicifolia. 


Phragmosporae. 

Coryneum. 

The conidial patches are black and disc-like, and rupture the 
host-epidermis. The conidia are oblong or spindle-shaped, 
yellowish, and pluriseptate ; they are abjointed from short 
conidiophores. 

Coryneum Beyerinkii Oud. 1 This is stated by Beyerink to 
be the cause of a “ gum-flux ” of cherry and allied species of 
Rosaceae. It is the conidial form of Ascospora (see p. 211). 

C. camelliae Mass. 2 occurs on living Camellia leaves at Ivew. 
(Britain.) 

Pestalozzia. 

Conidia spindle-shaped, with two or more brown median cells 
and hyaline terminal cells, the one at the free end carrying 
several ciliate processes. 

Pestalozzia Hartigii Tub. 3 The external effects of this 
disease have been long known, although the fungus causing it 
has only been recently detected. It attacks young plants of 
various trees and shrubs. The symptoms are yellow discoloration 
of the foliage, and constriction of the stem just above the level 
of the soil, followed by death of the whole plant. At the 
constriction of the stem the rind gradually dries up, whereas 
neighbouring portions continue to grow in thickness till finally 
the bark is ruptured (Fig. 302). In the living part of the 

1 Oudemans, kledwigia, 1883. 

2 Cooke, Grevillea, xx., p. 8, 1891. 

3 v. Tubeuf, Beitrdge zur Kenntniss d. Baumkrankheiten, 1888 ; and Forstlich- 
natunviss. Zeitschrift, 1892. 



Fig. 301 .— Putaloma Harligii. Young Borneo 
showing constriction just over the surface of the 
soil. (After v. Tubeuf.) 



Fio. 302 .— Pcfitalozzia I fartiffii . a. Beech 
seedling with a diseased constricted part on 
its stem, *. Two isolated conidia. (Aftor 
Roatrup.) 



PESTALOZZIA. 


493 


rind of young plants of spruce and silver fir, I succeeded in 
finding near the place of constriction, a delicate mycelial stroma 
enclosing some cavities (pseudopycnidia). Conidia were formed 
inside these cavities and emerged to the exterior. They belong to 
the genus Pestalozzia, and have two brown median cells, a trans- 
parent stalk-cell to which the long stalk is attached, and a 
transparent terminal cell carrying two or three transparent thread- 
like appendages (Fig. 303). Germination results in the emission 
of a strong germ-tube from one of the three lower cells. If at 
any time the conidia dry up, the two clear transparent cells 



Fig. 304 . — Pestalozzia funerea on Chamaecyparis Menziesii. At the places 
marked X cambium and rind have been killed, so that growth in thickness no 
longer takes place ; the higher parts, however, have continued to thicken, but 
are gradually dying, (v. Tubeuf phot.) 

collapse and the appendages easily fall off, so that on material 
of this kind the conidia are only two-celled and brown. The 
mycelium after cultivation in nutritive gelatine soon produces 
conidia. 

This fungus was found by Eostrup on beech, producing much 
the same effects as just described. On this host it has been 
found very destructive in young naturally regenerated forest, 
the loss in Bavaria and Wurtemburg within very recent years 
having been estimated at 30 per cent. It also occurs on ash, 
sycamore, and other trees. 

P. funerea Desm. (Britain and U.S. America). The spores of 


494 


FUNGI IMPERFECTI. 


this fungus were found by Boehm 1 on diseased cypress trees, and 
although investigations are not yet complete, it is believed that 
this Pestalozzia is the cause of a well-known disease on cypress. 
The symptoms on Cha maecyparis Menziesii are local constriction 
of stems' and branches, and death of portions beyond. The rind 
and cambium of constricted places are killed, the bark becomes 
split, and the wood dries up. P. funerea is a well-known sapro- 
phyte on twigs and needles of Cupressus, Junipcrus, and other 
Conifers ; its occurrence as a parasite has been suggested several 
times. 

P. gongrogena Tenime" is said to cause the canker of willow. 
In diseased willows Temme found an intercellular and an 
intracellular mycelium with pycnidia and conidia of Pestalozzia, 
but other pycnidia of unknown affinity were also present. 

P. insidiens Zab. On bark of Ulmus amcricana. (U.S. 
America.) 

P. phoenicis Grev. causes a disease on indoor cultivated palms. 

The following are some of the more important forms frequenting 
living leaves : 

P. Guepini Desm . 3 (U.S. America). The conidia of this species 
are found on large spots with dark margins on living leaves of 
Camellia japonica, Magnolia, Citrus, Rhododendron , and other 
plants. Spore-patches appear on the epidermis, and give off 
conidia embedded in a mucilaginous slime. The conidia have 
three dark median and two hyaline terminal cells, the distal one 
bearing the characteristic appendages. The leaves are permeated 
with mycelium and fall prematurely. 

P. inquinans C. et Hark. On Eucalyptus in California. 

P. stictica l>. et C. On Plat anus occvdentalis and Til ia in United States. 

P. concentrica I>. et Hr. On leaves of Crataegus , Pi/rus, Ciutanca, and 
Quercus in North America. 

P suffocata E. et E., and P discosioides E. et E. On cultivated and 
wild rose shrubs in America. 


Pestalozzina. 

Conidia similar to those of Pestalozzia, but all the cells 
hyaline. 

1 Zeitschrifl f Forst. u. Jagil-wesen, 1S94, p. 63. 

2 Thiel’s landwirth. Jahrhuch, ISS7 : and Her. il. deutsch. botan. Ots., 1 SiK). 

* Annal. des Science natter., Ser. 1 1 . , Vol. xin., 1S40; Briosi et Uuvara, Funghi 
parasit . , vi. 


PESTALOZZINA. 


495 


Pestalozzina Soraueriana Sacc . 1 occurs on foxtail grass 
{Alopecurus pratensis). The conidial tufts develop on spots which 
appear on the gradually withering leaves. The bristle-appendages 
on the terminal cell of the conidia are lateral, only one being 
terminal. This disease was first observed by Weinzierl at Vienna, 


Fig. 305 . — Septogloeum Ho.rtigioMu.rn on Acer campestre. The dead twigs exhibit 
black points and lines— the pycnidia of the parasite, (v. Tubeuf phot.) 

and has not as yet been found out of that neighbourhood ; it 
attacks the pure-culture seed-beds only. 

Septogloeum. 

Like Gloeo-sporium, except that it has pluricellular conidia. 

Septogloeum Hartigianum Sacc . 2 Twigs of the common 
maple {Acer campcstre) are subject to a disease, which exhibits 

1 Sorauer, Zeitschrift f. Pflanzenhrankheiten, 1894, p. 213. 

2 R. Hartig, Forstlich-naturvoiss. Zeitschrift, 1892, p. 289. 



496 


FUNGI 1MPERFECTI. 


itself in the drying-up of young twigs before their buds open 
in spring. The older branches, however, assume their normal 
foliage. Examination of diseased twigs reveals the mycelium 
of a parasitic fungus living both inside and between the 
cells of rind and wood. Conidial patches break through 
the host’s epidermis about May as long greyish-green lines. 
The conidia are hyaline, three-celled, and cylindrical with 
rounded ends ; the conidiophores are short thick rods. In May 
and June the spores are capable of infecting new hosts, and 
germinate in a few hours. Infection of twigs takes place in 
summer, and the mycelium spreads through the first-year 
shoots, without, however, giving any external indication of its 
presence till the following spring, when the twigs dry up as 
already described. 

S. ulmi (Fr.) may be a form of Phyllachora ulmi. The 
mycelium lives in parenchymatous cells, and causes the formation 
of brownish-yellow spots on leaves of the elm. The conidial 
patches form tiny points on the lower surface of the leaf ; they 
consist of pycnidia-like structures without a peridium, arising 
from a stroma developed under the epidermis. The conidia are 
spindle-shaped and pluricellular. 

S. mori (Lev.) is stated by Briosi and Cavara to produce yellow 
spots with brown margins on the leaves of Morus alba and M. nigra. 
Death and premature defoliation of the host then take place. 
The conidial patches develop under the epidermis, and rupture 
it as the conidiophores emerge ; they have no real peridium, 
hence the fungus cannot belong to the group Phlcospora, as 
Saccardo supposed. The conidia are long, cylindrical or fila- 
mentous, and pluricellular. 

Amongst the more important North American species are : 

S profusum (E. et E.). On living leaves of Corylv s 

americana. 

S fraxini Hark. On Fra.ntuus Oregana. 

S. apocyni Peck. On Apocynmn cannabinum. 


III. HYPIK )M YC’ETES. 

Conidia produced neither in pycnidia as in Sphaeropsideae, 
nor from a special stroma as in Melauconideae, but free on 
conidiophores given off front the mycelium. 


HYPHOMYCETES. 


497 


The group is subdivided into the families of the Mucedineae, 
Dcmatieae, Stilbeae, and Tubercularieae. 1 

i. FAM. MUCEDINEAE. 

1. Sect. Amerosporae. 

1. Subsect. Micronemeae. 


Oospora. 

Conidia, transparent or only slightly coloured, globose or 
ovoid, non-septate, and produced in regular chains from simple 
short conidiophores ; they thus resemble the genus Torula in the 
Dematieae. 

Oospora scabies Thaxt. 2 is said to cause the well-known 
scab or scurf on beet and potato. This consists in portions of 
the surface of the subterranean tubers swelling out as rough 
brown excrescences. Other authors ascribe this disease to 
bacteria. 

Microstroma. 

Conidia unicellular, transparent, oval, and shortly stalked. 

Microstroma album (Desm.). This, although common on 
living leaves of several species of Quercus, is not a serious 
disease. The conidia! patches on the under side of the leaves 
are white and very thin. (Britain.) 

M. juglandis (Bereng.) frequents the leaves of Juglans regia 
and J. cinerea in Europe and North America. 

Monilia. 

Conidia oval or spindle-shaped, and produced in chains from 
branched conidiophores. 

Monilia fructigena Pers. (Britain and U.S. America.) This 
is the cause of certain widespread diseases — the brown-rot of 
cherry and plum, the peacli-rot, and a rot on apples and pears. 
It has been the subject of many papers since Thiimen first 
described it in 1879. 3 All parts of the host are attacked, and 

1 This is the arrangement followed by Massee, “ British Fungus Flora” Vol. 
hi.; there the characters of the various sub-divisions may be obtained. (Edit.) 

2 Thaxter, Connecticut Arjric. Ex per. Station, Report, 1890. 

3 Amongst the more important descriptions are: Thiimen, Fungi Pomicola, 
1879; Smith (Worth. G.), Gardener’s Chronicle, 1885, p. 52; Arthur, Neiv York 
Agric. Exper. Station, iv., 1885. 


498 


FUNGI IMPKRFECTI. 


exhibit reddish or yellow spots ; therein the mycelium spreads 
rapidly and gives off tufts of conidiophores which rupture the 
epidermis. The conidiophores are septate, branched, and give 
off chains of unicellular oval conidia. Meanwhile the affected 
fruit becomes rotten and gradually shrivels up, it remains, 
however, hanging on the tree throughout the winter. During 



Fig. 306 . — Monilia frucligena. A, Apple showing the grey conidial patches as 
more or less concentric lines. IS, Young Peach, shrivelled up in consequence of 
attack, (v. Tubeuf del.) 


next spring, when the fruit is again moist, further conidia are 
given off. Infection takes place by wounds or even through 
the epidermis of young leaves and blossoms. The conidia have 



Fig. 307 . — Monilia frucligena. Branched conidiophore with chains of conidia. 
a, Branched hyp ha of Monilia in the tissue of an Apple, (v. Tubeuf del.) 

been found to retain their vitality for two years. Smith 1 
found that twigs were also affected by the disease, so that a 
gummy degeneration took place in the soft bast and cambium. 

As remedial measures, the gathering of all diseased fruit left 
hanging over winter is strongly recommended. This, as well 
as other diseased parts, should be burned as soon as possible. 

'Smith (Erwin), Journal of .Vy rolot/j/, VII., p. 36. 


MONILIA. 


499 


Washing of steins with a solution of iron sulphate in spring 
before the buds unfold is suggested, also spraying of young 
foliage with dilute Bordeaux mixture. 


Oidium. 

Mycelium epiphytic on living plants. Conidia unicellular 
and barrel-shaped, produced in chains on erect conidiophores. 
Many have already been proved to be conidial forms of 
Erysipheae. 

Oidium erysiphoides Fr. frequents living leaves of hop, 
clover, cucumber, etc., and is probably the conidia of species 
of Erysiphe on these hosts. (Britain and U.S. America.) 

0 . Tuckeri Berk. On leaves and berries of the vine (see 
Uncinula, p. 176). 

0 . leucogonium Desm. On roses; probably the conidial form 
of Sphaerotheca pannosa (see p. 172). 

0 . farinosum Cooke. On living leaves of apple-trees. 

(Britain.) 

0 . chrysanthemi Eabh. On leaves of cultivated chrysan- 
themum. (Britain.) 

0 . aceris Rabach. On leaves of Acer Pseudoplatanus. It is 
probably the conidial stage of Uncinula bicornis. (Britain.) 

0 . mespilinum Thiim. On leaves of medlar. (Britain.) 

0 . destruens Peck. On Amelanchier canadensis and Primus 
serotina in America. 

0 . tabaci Thiim. On leaves of tobacco. 

0 . monilioides Link, probably the conidial stage of Erysiphe 
graminis, occurs on living grasses over the whole world (see p. 1 7 5). 

2 . Sub-sect. Macronemeae. 

Botrytis. 

Mycelium grey. Conidia more or less spherical, and pro- 
duced in aggregations on the ends of branched conidiophores. 
Many of the species are saprophytes, others are parasitic on 
plants or insects, and others form sclerotia : the latter have 
already been considered under Sclcrotinia (see p. 267). The 
following are known to be parasitic on plants : 

Botrytis cinerea Pers. This enemy of many plants has already 
been noticed as Sclerotinia Fuckeliana ; so also B. Douglasu Tubeuf. 


500 


FUNGI IMPKRFECTI. 


B. galanthina Sacc. occurs on the bulbs of Galanthus nivalis 
in Britain. 

B parasitica Cav. produces sclerotia and conidia on Tulipa 
Gesneriana in Italy ( Sclerotium tulipae). 

B vulgaris Fr. 1 This is a very common species, and includes 
several well-marked varieties. It is said to be parasitic on 
cultivated lettuce causing a “ leaf-rot.” 

B fascicularis Sacc. is reputed to be the cause of a “ fruit- 
mould ” on the egg-plant ( Solanum Mclongena) in the United 
States. 

A Botrytis is figured by Atkinson 2 as frequent on diseased 
carnation-plants. 

Ovularia. 

Conidiophores simple except for tooth-like projections near 
the apex on which the conidia are developed. Conidia uni- 
cellular, colourless, solitary, rarely in chains. 

“ Closely allied to Ramularia, but distinguished by the one- 
celled conidia” (Massee). 

Ovularia pulchella (Ces.). Briosi and Cavara distinguish this 
as a disease of Lolium italicum in Italy. The leaves become 
black-spotted and permeated with an intercellular mycelium, 
from which arise the erect, branched, septate conidiophores. The 
more vigorous conidial patches have a delicate rose colour. 

0 necans Bass, produces large spots on the foliage of quince 
and medlar, so that the leaves gradually wither and dry up. 
Conidia appear as a white powder on the dead remains. This 
fungus is recorded from both Italy and France. 

The following are British species occurring on leaves; several 
of them, however, are placed by Saccardo under llamularia : 

Ovularia lychnicola (Cke.) Mass. On Fn/c/tnis diurntu 

O. senecionis (Sacc.). On Scnerio vulgaris. 

O lactea (Desm.). On species of Viola. 

O. armoraciae (Fuck.). On cultivated horse-radish. It is reported as 
somewhat destructive in the United States. 

O. interstitialis (H. et Hr.). On under surface of leaves of primrose, 
forming yellow spots in the angles of the veins. 

O primulana Thiim. On leaves of Primula . 

O. cochleariae (Cke.). On Cochlearia officinalis. 

1 Wehmer on species of Botrytis , Z< itschrift f. PJlamni kra n kh< ittu, 1S!M. 

2 Atkinson, “Carnation Diseasts at Amer. Carnation Society, 1 893. 


OVTJLARIA. 


501 


O. alnicola (Cke.). On A him glutinosa. 

O. scelerata (Cke.). On Ranunculus sceleratus. 

O. rosea (Fuck.) produces irregular brown spots on the leaves of 
various species of willow. 

O. asperifolii (Sacc.). On Symphytum officinalis. 

O. veronicae (Fuck.). On spots on leaves of Veronica Ckamaedrys, etc. 
O. lamii (Fuck.). On Lamium. 

O. syringae (Berk.). On Syringa. 

O. sphaeroidea Sacc. causes spots on leaves of Lotus. 

O. carneola Sacc. On spots on leaves of Scrophularia nodosa. 

O. bistortae (Fuck.). On spots on leaves of Polygonum Bistorta. 

O. obliqua (Cke.). On leaves of Rumex. 


2. Sect. Didymosporae. 

Didymaria. 

Conidia two-celled, colourless, and produced singly at the 
extremity of simple erect conidiophores. 

Didymaria prunicola Cav. Cavara states that this causes 
raised roundish spots on the upper surface of leaves of plum ; 
finally the leaves gradually dry up and fall off. Slender two- 
celled conidiophores are produced, and give oft' each a two-celled 
obovoid conidium. 

D. Ungeri Cord. On living leaves of Ranunculus repens. (Britain.) 

D. astragali (Ell. et Hoi.). Found on leaves of Astragalus canadensis. 
D. spissa Hark. On leaves of Solidago occidentalis ; both species in 

North America. 


Bostrichonema. 

Conidiophores erect, spirally twisted, unbranched, and non- 
septate. Conidia elliptic or oblong, two-celled, and hyaline. 

Bostrichonema alpestre Ces. On living leaves of Polygonum 
viviparum and P. Bistorta. (Britain.) 

B. modestum (B. et B. White). On leaves of Alchemilla 
alpina. (Britain.) 


3. Sect. Phragmosporae. 

Ramularia. 

Conidiophores emerging in tufts from the stomata ; they give 
off a terminal conidium, then bend over and produce a lateral 
conidium, and so on they branch in a sympodial manner, pro- 


502 


FUNGI IMPERFECTI. 


ducing conidia at the end of each branch. Conidia septate 
oval or cylindrical, and light-coloured. 

“ The parasitic habit, simple or sparingly branched hyphae, 
denticulate and bearing the septate conidia at the tips, charac- 
terize the genus, which differs from Ovularia only in the 
septate conidia” (Massee). 

Ramularia cinarae Sacc. is said by Prillieux 1 to have caused 
great destruction in the cultivation of artichokes. The leaves 
became spotted and died, so that no flower-heads were produced. 

The following are British species : 

Ramularia hellebori Fuck. On leaves of Helleborus foetid us and //. 
viridis. 

R. epilobii (Selin.). On leaves of Epilobium. 

R. ulmariae Cooke. On leaves of Spiraea Ulmaria. (U.S. America.) 

R. geranii Fuck. On under surface of leaves of various species of 

Geranium. 

R. lampsanae (Desin.). On Lampsana and Hypochoeris. 

R. pruinosa Speg. On Senecio jacobea. 

R. plantaginis El. et Mart. On leaves of Plantago major. (U.S. Am.) 

R. variabilis Fuck. On leaves of Digitalis and Verbascum. (U.S. America.) 

R. calcea Ces. On leaves of Gfechoma hederacea. 

R. urticae Ces. On leaves of species of Urtica. (U.S. America.) 

R. pratensis Sacc. On Humor Acetosa. 

R. rufibasis (B. et Br.). On Myrica Gale. 

Some of the more important North American species are : 

Ramularia rufomaculans Peck. On the buckwheat ( Fagopyrum esnden- 
turn), it has proved a somewhat injurious fungus. 

R. albomaculata Peck. On leaves of Garya americana. 

R viburni E. et E. On leaves of Viburnum Lenta go. 

R celtidis E. et K. On leaves Celtic occidental in. 

R. desmodii Cooke. On leaves of various species of Desmodium. 

R. brunnea Peck. On living Tmsilago farfara. 

R. areola Atks . 2 This causes spots on the foliage of cotton. 
“Spots amphigenous, pale at first, becoming darker in age; 
irregular in shape, limited by the veins of t ho leaf, conidia in 
profusion giving a frosted appearance to the spots. Conidio- 
phores fasciculate, in small clusters distributed over the spots. 
Conidia oblong, usually abruptly pointed at the ends” (Atkinson). 

R Goeldiana Sacc. is said to kill leaves and twigs of Copt a 
arabica in Brazil. 

1 “ Maladie d. Artichauta,” Hulbiiii <b la ,*oc. myeoloy. d t France. 1892. 

3 Atkinson, Botanical Gnzcltt , xv., 1890, p. Kid. 


PIRICULARIA. 


503 


Piricularia. 

Conidia grey, pluricellular, somewhat pear-shaped, and pro- 
duced from the apex of simple erect conidiophores. 

Piricularia oryzae Br. et Cav. This species is described 
by Briosi and Cavara as causing a disease of rice in Northern 
Italy. The plants become spotted and reddish-brown in summer, 
finally withering. The conidiophores arise on the spots on the 
lower surface of the leaf, and bear light-grey three-celled 



Fig. 30S . — Mastigosporiwm album, (v. Tubeuf del.) 


conidia. Diseased plants may be found bearing this fungus 
only, frequently however it is in company with other fungi. 

Cercosporella. 

Conidia hyaline, similar to those of Ccrcospora, and produced 
from simple or branched hyaline conidiophores. 

Cercosporella persica Sacc. is parasitic on living leaves of 
peach. In America it has been known since 1890, and receives 
the name of “ frosty mildew.” It causes yellow spots on the 
lower surface of the leaf. 

C. pastinacae Karst, occurs on living leaves of cultivated 
parsnip. 


504 


FUNGI IMPERFECTI. 


Mastigosporium. 

Conidia hyaline and four-celled, frequently bristled. 
Mastigosporium album Iiiess. produces oblong dark spots 
with light margins on leaves of living grass. The conidia 
are produced on the margins of the spots (Fig. 308). 


Fusoma. 

Similar to Fusarium, but the mycelium is loose and not 
aggregated into a tuft. Conidia spindle-shaped and septate. 



Fio. 809 . — Fusoma parasitirum. Dis- 
eased Pine-seedlings, with, a, root killed ; 
b, hypocofcyl killed ; r, first leaves and 
plumule killed. (After K. Ilartig.) 



Fio. .*110. — Epidermis of a Pine-seedling 
with a stoma. Some hyphae of Fusoma 
have produced partial dissolution of cell- 
walls. (After It. Ilartig.) 



Flu. 311. — Fusoma parasiticum. Coni- 
dia- immature, mature, and germinat- 
ing. (After It. Ilartig.) 


Fusoma parasiticum Tub. 1 is the cause of a disease of seed- 
lings, particularly those of Conifers. The first symptoms are 
dark patches on the seedlings, followed by their collapse. I'here- 

1 It. Hartig, ForaUich-uaiunoiii*. Ztitxchr\fl, ISU.’t, p. 43*2. 


FUSOMA. 


505 


after in moist weather or under artificial cultivation, a 
light-grey mycelium appears bearing numerous slightly curved, 
tapering, pluriseptate conidia (Fig. 311). In Bavaria and 
Baden this parasite has caused great loss in the seed-beds of 

conifers. 

F. inaequale Hoyer. On living leaves of Taraxacum officinale. 


Septocylindrium. 

Conidia cylindrical, hyaline or pale-coloured, with two or 
more septa, and produced in chains. 

Septocylindrium aromaticum Sacc. occurs on living Acorus 
Calamus, killing leaves and even plants. The mycelium grows 
intercellularly and produces spots. The conidiophores emerge 
in tufts from stomata included in the spots, and give off long 
thread-like, pluriseptate, hyaline conidia. 


2 . FAM. DEMATIEAE. 

1. Sect. Amerosporae. 

1. Subsect. Micronemeae. 

Many of the genera of this subsection contain species found 
on the living leaves of plants, but none of them are yet of 
economic importance. 


2. Subsect. Manronemeae. 

Hormodendron. 

Mycelium grey, epiphytic, and creeping. Conidiophores erect, 
branched, and septate. Conidia spherical or ovoid, unicellular, 
and produced in chains. 

Hormodendron hordei Br. 1 This produces a characteristic 
spotting of the haulms and leaves of barley, accompanied by a 
stunting of the whole plant and poor development of the ears. 
This is not a true parasite, but when it appears in quantity 
it has considerable effect, attacking whole fields and causing 
great injury. The spots and -conidia are found also on wild 
Hordcum murinum on the margins of roads and fields. 

1 Bruhne in Zopf’s Beitrage 2 . Physiol, u. Morphol. niecl. Organismen, iv., 
1894 . 


506 


FUNGI IMPERFECTI. 


2. Sect. Didymosporae. 

1 . Subsect. Micro aemeae. 

Dicoccum. 

Conidia oblong, two-celled, and arising from short simple 
conidiophores. Mycelium subcuticular. 

Dicoccum (Marsoniai rosae (Bon.) causes brown spots on 
living leaves of roses, and a premature leaf-cast takes place. 
Little mycelial stromata develop between the epidermal cells 
and their cuticle, and give off two-celled hyaline conidia. 

D uniseptatum B. et Br. forms dark patches on twigs of 
Clematis vitalba. (Britain.) 

D lathyrinum Ell. et Gall. On living leaves of Lathyrus 
ochroleucm in America. 


Cycloconium. 

Mycelium subcuticular. Conidia one- to three-celled. 

Cycloconium oleaginum Cast . 1 When this fungus is present, 
the leaves of the olive show roundish light-brown spots with 
dark margins, then becoming discoloured, they roll up and drop 
off. The mycelium grows in the walls of the epidermal cells, 
branching dichotomously ; branches of the hyphae break out 
through the cuticle as sac-like cells, which become the conidio- 
phores. The conidia consist of one to three cells. Kruch 
states that Cercospora cladosporioul es is often present along with 
this disease of the olive, and may take some part in causing it. 

Peglion states that this or an allied species occurs on leaves 
of Qucrcus Ilex. 


2 . Subsect. Macronemene. 

Passalora 

Conidia oblong or spindle-shaped, two-celled, and borne on the 
apex of greenish pluriseptate conidiophores, arising from an 
olive-green mycelium. 

Passalora bacilligera M. et Fr. occurs on living leaves of 

Alnus glutinosa. (Britain.) 

P. microsperma Fuck. This frequently covers the whole 
lower surface of the leaves of Abuts incatict with little tufts of 


1 Kruch, Bulletin soc. hot. ital . , 1892. 

Hoyer, Kechercht* stir Its maladu .« «/< I'Olirier, Montpellier, 1892. 


PASSALOKA. 


507 


brown septate conidiophores, bearing long, two- celled, obovate 
conidia. 

Fusicladium. 

Mycelium greenish and sparingly septate. Conidiophores in 
tufts, short, erect, and bearing terminal conidia. Conidia ovoid 
or clavate, and one or two-celled. 

The species are conidial forms of Venturia, and have already 
been considered. Some of the better-known forms are : 

Fusicladium dendriticum Wallr. (Britain and U.S. America). 
This attacks the leaves, shoots, and fruits of the apple (see p. 2 1 8). 



Fig. 312. — Venturia (Fusicladium) dendriticum forming brown spots on an 
apple ; those still in the earlier stages have a radiate margin and bear conidia. 

The enlarged section shows two rows of large-celled parenchyma of the apple, 
covered by a stroma of pseudoparenchyma bearing conidiophores and conidia. 

(v. Tubeuf del.) 

F. pirinum (Lib.) (L T .S. America). This is a cause of 
“ spotting ” on leaves and fruits of the pear, also of species of 
Crataegus and Amelanchier. The conidial patches are brownish 
in colour. Peglion states that this parasite forms sclerotia in 
the bark of twigs. It is probably a conidial form of Venturia 
ditricha var. jpyri. 

F. cerasi (liabh.) attacks the cherry orchards with such 
virulence that the crop may be rendered cpiite unsaleable. 

F. eriobotryae Cav. 1 Cavara states that this attacks the 


1 Cavara, lit vista di Patologia Vegetate, 1892. 



508 


FUNGI IMPERFECTI. 


leaves of Mespilus (Eriobotrya) japonica causing them to become 
spotted and to wither. The hyphae live in the epidermis, 
and form a stroma from which conidia are given off. 

F. tremulae Frank. Frank 1 gives this as the cause of a 
disease of the aspen ( Populus tremula). The leaves turn 
brown and fall, the shoots in consequence soon drying up. 
Conidia are developed on the surface of dead leaves and ger- 
minate on living leaves of aspen, producing a germ-tube which, 
after forming an adhesion-disc, penetrates into the cavity of 
the epidermal cells. 

F. depressum B. et Br. is found on living leaves of Angelica *ylve*tris. 
(Britain and U.S. America.) 

F. praecox Rabli. On living leaves of Tragopogon orientalis. 

F. sorghi Pass. On living leaves of Sorghum halepense. 

T1 le following are North American species : 

F. caryogenum Ell. et Langl. On leaves of Carya olivaeformu. 

F. effusum Wint. On leaves of Carpinus americana. 

F. destruens Peck. On living Arena sativa. 

F. fasciculatum ( '. et E. On leaves and steins of Euphorbia. 


Scolecotrichum. 

Mycelium greenish. Conidia oblong or oval, produced both 
terminally and laterally on the conidiophores. 

Scolecotrichum melophthorum (Prill. et Del.).-’ This pro- 
duces a melon disease in France known by the name “ Nude.” 
It consists in the fruits and stems becoming spotted, the tissue 
being completely destroyed. 

Sc. graminis Fuck. Occurs on grasses, especially on the oat. 
Pammel 3 reports it as also injurious on barley during 1891, 
in some parts of t he United States: the diseased leaves were 
marked with brown or purplish brown spots. 

Sc. fraxini Pass. On living leaves of Frcurinus excelsior 
and F. Ornus. 

Cladosporium. 

Mycelium greenish. Conidia globose or ovoid, one to four- 
celled, and of variable form. The species are mostly sapro- 
phytes on substrata of all kinds. 

1 Be r. </. tUutsch. botan. Oene.ll, 1S8I!, p. 29. 

-Bulletin (h In nor. mycolog. <1 France, 1891. 

'Journal oj' Mycology, vn., p. 9(5. 


CLADOSPORIUM. 


509 

Cladosporium herbarum (Pers.). This species is found every- 
where on dead plant remains, but it is also common on living- 
leaves of many plants. The first suggestion that this form 
might occur as a parasite came from Haberlandt 1 and Frank . 2 
It possesses a dirty-grey, thick, septate mycelium, which may 
be colourless when young or growing inside a substratum ; it 
applies itself closely to the surface of plants and even pene- 
trates through the stomata or cell-walls into the tissues. The 
conidiophores are erect, otherwise variable in form ; they give 
off conidia from the apex or from lateral processes. The 
conidia are oval and contain a variable number of cells. Organs 
of plants attacked show grey spots, and withered parts if they 
are still alive. 

The following are some of the papers describing Cladosporium 
herbarum as, in certain circumstances, a parasite. Prillieux and 
Delacroix , 3 on apple-trees and raspberry-bushes ; Cavara , 4 on 
raspberry, cycads, agave, and other plants ; Sorauer , 5 * on peas. 
Lopriore" describes this fungus as the cause of a “black” 
disease on ears of wheat ; the results of infection were how T ever 
somewhat variable. 

Ritzema Bos reports it as producing disease, and in some 
cases death, in fields of oats. Kosmahl and Nobbe 13 found 
that seedlings of Pinus rigida blackened and died suddenly in 
the beginning of May, apparently from the attacks of this 
fungus. Janczewski 7 states that this Cladosporium is a conidial 
form of Sfthaerella Tulasnei, a new species of Ascomycete 
established by him . 8 

Cl. elegans Penz. This causes on the orange a disease or 
“scab,” which has been injurious both in Southern Europe and 
the Southern States of America . 9 * * It attacks chiefly wild orange 

1 Fruhling’s landwirth. Ze.itu.ng, 1S78. 

2 Die Krankheiten der Pflanzen, 2nd Edit., 1896, ii., p. 292. 

3 Bulletin de la soc. mycolog. de France, vn. 

4 Revue mycologique, 1891. 

5 Handbuch d. PJlanzenkrankheiten, 1886. 

B Berichte d. deutsch. botan. Gesell, 1892 ; Landwirth. Jahrbuch, 1894. 

7 Extraits du Bxdlelin de I’Academie des sci. de Cracovie, 1892, 1893, 1894. 

8 Schostakowitseh (Flora, 1895 (ergzbd. ) distinguishes Cladosporium from other 
genera. 

9 Scribner, Bulletin of Torrey Club, xm., 1886, p. 181. Underwood, Journal of 

Mycology, vu., p. 34. Swingle and Webber, “Diseases of Citrous Fruits,” 

U.S.A. Dept, of Agriculture Bulletin 8, 1896. 


510 


FUNGI IMPERFECTI. 


trees, more rarely the sweet orange and lemon. The disease 
first appears as whitish or cream-coloured spots on leaves, young 
twigs, or fruit. If the spots are numerous the leaves become 
badly curled or twisted, and covered with wart-like eruptions. 

Cl. viticolum Ces. is regarded as a dangerous parasite of the 
vine. 

Cl. carpophilum Thiim. This species has been found para- 
sitic on plum and peach in the United States. Its mycelium 
creeps over the surface of leaves and fruit, causing pale-coloured 
spots which extend and run together, spoiling the appearance 
of the fruit. The disease as yet does not appear to have a very 
wide distribution, nor is it directly very injurious, but as 
cracking of the ripe fruit occurs when it is present, the way is 
opened for entrance of fruit-destroying fungi. 

Cl condylonema Pass, also occurs on leaves of the plum. 
It causes leaf-spot and leaf-curl. The mature conidia have 
fine spines on their coat. 

Cl fulvum Cooke. (Britain and U.S. America.) This is the 
cause of a disease of tomato. It attacks leaves and shoots of 
plants cultivated indoors, and soon anises their death. Prillieux 
and Delacroix 1 have described a somewhat similar disease in 
France, found, from artificial infection, to be produced by some 
species of Cladosporiuvi, but whether this particular species, 
they did not state. 

Cl cucumerinum E1L et Arth. 2 causes a disease of cucumber 
Frank 3 describes a disease which he found to be due to a 
Cladosporium (Cl. cucumeris n. sp.). This attacked the fruit of 
both cucumbers and melons in cultivation under glass at Berlin, 
and caused great damage : brown rotten depressions appeared 
on the fruits, and thereon the tufts of conidiophores. 

Cl. macrocarpum I 'reus, causes a “scab” disease of spinach in 
the United States (A"../. Auric. Ec/xt. Station Bulletin, 70, 1800). 

Other species that may be parasitic are : 

Cl. pisi Cug. et Macc. On living pods of Pimm tali rum in Italy. 

Cl. epiphyllum Mart. On leaves of Quercno, Plata ntut, Populus, Hedera^ 
etc. (Britain and U.S. America.) 

Cl. juglandinum Cooke. On leaves of the walnut. (Britain.) 

1 Bulletin de la soc. myroloij. de France, 1891. 

2 Description in Mats. Acjric. Ex pc r. Station Report, 1892. 

Zeitschri/t f. Pflautenkrankheiten, in., 1893. 


CL ADOSPO RIUM. 


511 


Cl. Scribnerianum Cav. On leaves of Betula popidifolia in America 

and Italy. 

Cl. hypophyllum Fuck. On leaves of Ulmus campestris. 

Cl. tuberum Cooke. In the tubers of Batatas edulis in Carolina, U.S.A. 


3. Sect. Phragmosporae. 

1. Subsect. Micronemeae. 

Clasterosporium. 

Conidia brownish, cylindrical or spindle-shaped, and consisting 
of three or four cells. 

Clasterosporium amygdalearum (Pass.) attacks the leaves of 
almond, peach, apricot, cherry, and plum. An intercellular 
mycelium has been found, and roundish dry spots with reddish 
margins are formed. Thereon tufts of short conidiophores are 
developed, bearing cylindrical, thick-walled, pluricellular conidia. 

Cl. glomerulosum Sacc. (Sjjoridesmium glom. Sacc., 1878, and 
Pleospora conglutinata Goebel, 1879). Goebel 1 first described 
this species as a parasite on Juniperus communis. A colourless 
intercellular mycelium is present, and in consequence the 
needles turn brown, die, and fall off 
prematurely. On the upper side of 
the needle the mycelium emerges 
through the stomata, and forms 
dark -grey coils from which the 
grey, ovoid, pluricellular conidia are 
given off. 

Ceratophorum. 

Conidia brownish, spindle-shaped 
or cylindrical, three or more celled, 
the upper cell with terminal 
bristles. 

C. setosum Kirch. Dark spots occurring on the leaves, 
petioles, and shoots of young plants of Cytisus Laburnum, etc., 
were found to enlarge and bring about death and defoliation. 
Kirchner found the leaf-tissue permeated by a colourless septate 
mycelium, which gives off conidia on both sides of the leaf. 
The conidia resembled those of Pcstalozzia, but their cell-number 

1 Wurtemburg naturwiss. Jahreshefte, 1879. 

Zeitschrift f. Pflo.nzenh-ankhe.iten, 1892, p. 324. 



Fig. 313. — Ceratophorum setosum on 
Cytisus capi.tu.tvs. Leaf with diseased 
apices. An isolated spore with its 
appendages. (After Kirchner.) 


512 


FUNGI IMPKRFECTI. 


was variable, and the terminal cells, although lighter than the 
median, were not quite hyaline. The terminal cell bore several 
very long bristles. 

C ulmicolum E. et K. On living leaves of Ulmus fulva in 
America. 

Helminthosporium. 

Conidia brown, cylindrical or spindle-shaped, and pluricellular. 
Mycelium well-developed and brownish. 

“ 1 listinguished from Cladosporium by the conidia being more 
than one-septate at maturity ” (Massee). 

Helminthosporium gramineum (Eabenh.) 1 This causes a 
disease on barley, both in Europe and the United States ; as yet, 
however, it is not very common. It attacks generally the lower 
leaves, producing long, narrow, dark-brown spots with yellow 
margins. The leaves so attacked gradually wither, but do not 
prejudice the yield of grain seriously. On the spots are 
developed the black septate conidiophores, each' with a large 
black conidium with from two to eight cross-septa. 

H turcicum Pass, causes long spots on the leaves of Zea mats 
both in Italy and America. The spots are yellow with indistinct 
dark margins, and from them arise patches of grey septate 
conidiophores. The conidia resemble those of the species last 
described, so that some authorities regard the two forms as one. 
Briosi and Cavara describe the mycelium as consisting of 
branched septate hyphae, the cells of which frequently become 
irregularly swollen. The young Indian corn leaves are killed, 
and the crop may, in consequence, be seriously injured. 

H. teres Sacc. This is a form of II. gramineum which 
Briosi and Cavara distinguish as occurring on oats. Infection 
takes place at the apex of the leaves, and the mycelium spreads 
through the parenchyma causing elongated dry spots, so that 
the leaf ultimately dries up and dies. The conidiophores are 
developed singly, not in tufts, and the conidia are smaller than 
those of H. gramineum. The conidia are greenish, thick-walled, 
pluricellular, and produced terminally. 

H gracile (Wallr.) causes long marginate spots on the leaves 
of Iris gcrmanica. 

1 Eriksson, Bo! an. CentralMatt, xxix., ISS7. Kirch nor, Zdtschrift f. Pflanzen- 
krankheitm, i., 18511. p. 24. 


CERCOSPORA. 


513 


Cercospora. 

Conidia elongated and slender, olive-green, and septate. My- 
celium greenish. 

“ Distinguished by the vermiform septate conidia ” (Massee). 

Cercospora circumscissa Sacc. 1 This is a parasite which 
occurs on cultivated almond, peach, and nectarine, as well as 
on wild Prunus serotina in the United States. The leaves are 
attacked while still young, and exhibit by reflected light a 
yellowish spot with a dark centre. The conidia arise on the 
spots as dark-green clusters, thereafter the diseased tissue shrinks, 
becomes detached, and falls out, leaving “ shot-holes ” not 
unlike those produced by species of Pliyllostida. Defoliation 
may occur in severe cases of attack. As a result of the 
injury to the foliage, the new wood does not mature well, 
and second growth may take place during the same season ; 
shoots of this kind will probably dry up during winter. The 
fungus may also directly kill the tissue of twigs as far as the 
cambium. The fruit is never attacked directly, but may be 
seriously affected through the injury to leaves or twigs. 

In order to minimize the disease, it is recommended to burn 
all fallen foliage, and to turn the earth thoroughly below infected 
trees. Pierce obtained a crown of very healthy foliage on almond 
trees treated with (1) ammoniacal solution of copper carbonate, 
and (2) modified eau celeste. 

C. persicae Sacc. On leaves of peach. (U.S. America.) 

C. acerina Hartig 2 appears on brown spots on the cotyledons, 
young leaves, and stalks of young plants of Acer. The conidia 
are grey, pluricellular, and slightly curved (Pig. 314). The 
mycelium inhabits the intercellular spaces of the parts attacked, 
and forms resting sclerotia in the tissues of dead leaves. 

C. viticola (Ces.). 3 This fungus is found in Europe and the 
United States on Vitis vinifera and V. Labrusca. It causes 
spots on the leaves, and from these arise close columns of 
septate conidiophores which give off thick pluricellular conidia. 

C. beticola Sacc. 4 inflicts considerable injury on cultivated 

fierce, Journal of Mycology, vii., p. 66 and p. 232. 

2 R. Hartig, Untersuchungen aux d. forstbotan. Institut, i., Munich. 

3 Description and treatment in New York Agric. Exper. Station Report for 
1890, p. 324. 

4 Thumen, Die Bekampfung d. Pilzkrankheiten vnserer Kxdturgewdclise, 1886. 


514 


FUNGI IMPERFECT!. 


sugar beet and beet-root. It is easily recognized by the 
numerous sharply defined spots produced on the leaves. The 
conidia are very long and pluriseptate. In the United States 
this is one of the most serious of beet diseases . 1 As preventive 
treatment, great care should be taken to destroy all infected 
material. A long rotation should also prove a good remedy. 



Fio. 314. — LYrro*/>ora an -rina. 2, Seedling of An ,-, with a cotyledon brown and 
withered, and a leaf partially so. 4, Section through a diseased cotyledon ; the 
conidiophores ( d ) emerge from the epidermis, and bear long tapering septate 
conidia; sclcrotia formed inside the diseased tissues for hibernation. 5, Ger- 
minating conidia. (After R. Uartig.) 

C apii Fres. Common on celery (Apiitm graved? ns) and par- 
snips (Paslinaca saliva) throughout all Kurope and North America. 
It causes leaf-spots at first yellowish then enlarging and turn- 
ing brown. The mycelium grows in the intercellular spaces of 
the leaf, and gives off tufts of conidiophores through the 
stomata. The conidia are long, tapering, obclavate bodies with 
an attachment-scar at their larger end . 2 

C asparagi Sacc. occurs on asparagus in Italy; C. caulicola 
Wint. frequents the same host in America. 

C Bloxami B. et Br. On Brass ica in Britain. 

C armoraciae Sacc. On horse-radish. 


1 Pummel. lout i Agrie, Ex per, Station Bulletin, 15. 1891. 

J Description in Xnr Jersey . I grir. Ex/icr. Station Bulletin 2 , 1891. 


CERCOSPORA. 


515 


C. resedae Fuck . 1 This fungus is the cause of a garden 
mignonette disease very common in America and Europe. It 
causes little depressed spots with brownish or yellowish borders, 
which begin as reddish discolorations of the leaf. The leaves 
gradually wither and dry up, so that the flowers suffer. The 
mycelium grows inside the leaves, and gives off tufts of conidio- 
phores through the stomata. The conidia are elongated, septate, 
and spindle-like or club-shaped. Spraying with Bordeaux 
mixture was found to give good results. 

C. cheiranthi Sacc. produces roundish leaf-spots on wall- 
flower, and, if severe, causes death of the leaves and premature 
defoliation of the plants. 

C. rosaecola Bass. This causes leaf-spot on cultivated and 
wild roses in the United States. The first indication of disease 
is the appearance of black spots with reddish margins. The 
conidiophores emerge from the stomata in tufts, and carry long 
obclavate conidia. 

C. angulata AYint. is one of the causes of leaf-spot on 
currant, and occurs often in company with Septoria ribis. (U.S. 
America.) 

C. violae Sacc. occurs on leaves of Viola odorata. 

C. malvarum Sacc. On species of Malva. 

C. althaeina Sacc. On hollyhock in the United States. 

C. neriella Sacc. causes leaf-spot on Nerium Oleander. 

C. Bolleana (Thum.) produces olive-brown spots on leaves and fruits 
of the Fig, injuring the crop. 

C. capparidis Sacc. On Capparis spinosa in Italy. 

C. gossypina Cooke is given by Atkinson as a fungus frequently present 
on diseased plants of cotton. 2 

Saccardo records over 230 species of Cercospora, most of which cause 
spotting of living or fading leaves of many plants, e.g. Phaseolus, Lupinus, 
Trifolium , Vicia, Gleditschia, Solanum nigrum , Datura , Ricinus, Ampelopsis, 
Liriodendron , Tilia, Rosa, Potentilla, Rubus, Cydonia, Ptelea, Rkamnus, 
Euonymus , Ailanthus, Rhus, Sambucus, Viburnum, Olea, Syringa, Morus, 
Fraxinus, Coffea, Ligustrum , Mercurialis, etc. 


Heterosporium. 

Conidiophores simple or branched. Conidia olive, oblong, 
pluriseptate, and with a spiny or warty outer coat. 

1 Fairchild in Report of Section of Vegetable Pathology for 1889, U.S. Dept, 
of Agriculture. 

2 Botanical Gazette, 1891, p. 61. 


516 


FUNGI IMPERFECTI. 


“Kesembling Helminthosporium in general habit and structure, 
in fact only distinguished by the minutely warted conidia ” 
(Massee). 

Heterosporium echinulatum (Berk.). 1 (Britain and U.S. 
America.) The “ fairy ring spot ” of Carnations. This is a 
serious enemy of cultivated carnations, and causes great damage. 
It was first described by Berkeley in 1870 as a carnation pest. 
The symptoms are light-coloured spots on which are concentric 
rings of dark-coloured conidiophores. These arise from dark- 
coloured portions of the mycelium inside the leaf and give off 
conidia with three or more cells. The conidia are at first 
terminal, but after one has been formed the conidiophore 
branches laterally and produces another conidium, repeating this 
process for a considerable time. The spots are produced on 
leaves, leaf-stalks, and sepals, causing them to wither. In 
consequence the flowers do not unfold and the plants are 
rendered unsightly. 

Cultivation of the carnation in dry airy conditions is said 
to keep this disease in check. 

The following are British species occurring generally on 
lading leaves : 

H. variabile Cooke. On spinach. 

H. ornithogali Klotzsch. On Ornithogalunt, Convallaria , and other 
species of Liliaceae. 

H. typharum C. et M. On Ti/p/ia anrjusti folia. 

H. laricis C. et M. On larch needles. 

H. asperatum Massee. 2 Occurs as a parasite on Smilaciva stellatu. 


Napicladium 

Conidia oblong, three or more celled, and produced singly 
on the end of short conidiophores. 

“Somewhat resembling Hclmiiifhosjwriiim and Bi'achi/sporium , 
but distinguished by the less rigid fertile hyphae and the 
large solitary conidia ” (Massee). 

Napicladium (Helminthosporium) arundinaceum (Cord.). 
(Britain.) This lives parasitic on the leaves of Phragmitcs 
communis, and spreads rapidly from plant to plant. The leaves 

1 Worth, (i. Smith, Gardener's Chronicle, xxvi., 1886, p. 244. 

Atkinson. “ Carnation Diseases" at American Carnation Society, 1898. 

5 Massee, American Journal of Microscopy, February, 1898. 


NAPICLADIUM. 


517 


become coated with conidia and assume a leaden grey colour, 
so that in many cases only the points remain green. Finally 
the attacked leaves die and dry up. 


4. Sect. Dictyospoeak. 

1. Subsect. Micronemeae. 

The forms included under genera of this group (e.g. Sporo- 
desmium and Coniothecium ) have as yet been little investigated 
in regard to their parasitic nature. 


2. Subsect. Macronemeae. 

Macrosporium. 

Conidia grey, muriform, and borne on the apex of simple or 
branched conidiophores. 

Macrosporium sarcinaeforme Cav. 1 Cavara describes a 
browning and death of a whole field of red clover ( Trifolium 
pratense), and ascribes it to this fungus. Minute spots were 
produced, at first light-coloured, then brown, finally coalescing 
so as to cause drying-up of the whole leaf. The short thick 
conidiophores were developed on the lower surface of the leaf, 
and gave off pluricellular terminal conidia. 

M. solani Ell. et Mart. This is described 2 as occurring along 
with the “black -rot” of the tomato in the United States. It is 
said to cause a rot in the fruit and a leaf-blight on both tomato 
and potato. Along with this species there also occur a Fusarium 
(p. 520) and frequently a Cladosporium ; as yet the relationships 
of the different forms, and the part they take in causing the 
diseases ascribed to them, is but imperfectly investigated. 

Sorauer 3 ascribes a disease on the potato in Germany to this 
species or to an Alternaria (A. solani). He also believes that 
it is the cause of the “ early blight ” of American potato crops, 
but further investigation is still required. 

Many other species of Macrosporium have been described on 
plants of economic importance, yet most of them occur only on 
parts somewhat faded or languid, so that they cannot be regarded 

1 Briosi and Cavara, Funghi parasit. , v. 

-Report of the Section of Vegetable Pathology for 18SS, U.S. Department of 
Agriculture. 

3 Ztilschrift f. / ‘fanzeukran kheiten, 1896, p. 1. 


518 


FUNGI IMPERFECTI. 


as important parasites. Amongst these are the following British 
and North American species : 

M. brassicae Berk. On cabbage, generally somewhat decayed. 

M. sarcinula Berk. On cucumber. 

M. nobile Vize. On Dianthus. 

M. alliorum C'ke. et Mass. On onion. 

M. ramulosum Sacc. On celery. 

M. catalpae Ell. et Mart. On Catalpa Bignonioides. 

M. nigricantium Atks. is a semi-parasite accompanying other diseases 
of the cotton plant. 

Mystrosporium. 

“ Allied to Macrosporium, but distinguished by the more rigid 
and darker- coloured hyphae and conidia ” (Massee). 

Mystrosporium abrodens Neumann . 1 This is described as 
the cause of a disease which destroyed one-tenth of the total 
wheat-crop in the Haute- Garonne of France. The fungus 
attacked the nodes and leaves, forming dark patches ; the nodes 
were weakened and frequently broke over, while the ears were 
badly developed. 

Alternaria. 

Conidia grey, muriform-septate, flask-shaped, and borne on 
short simple conidiophores. 

“ Distinguished by the clavate or flask-shaped muriformly 
septate olive conidia being united in chains and connected 
by narrow isthmus-like portions ” (Massee). 

Alternaria brassicae (Berk.) (Britain). This species causes 
on leaves roundish black spots marked with concentric brown 
zones. The mycelium lives in the leaf-parenchyma and gives 
off tufts of conidiophores through the stomata. Briosi and 
Cavara state that it causes considerable damage to Brassica 
oleracea, Cochlcarin officinalis, and Armoracia. (Probably the 
same species as Polydcsmus exitiosns Kuhn.) 

Other diseases have been ascribed to species of Alternaria. 

Septosporium. 

Conidia brown, and muriform-septate. Conidiophores of two 
kinds — short and fertile, or elongated and sterile. 

Septosporium heterosporum Ell. et Gall, causes a leaf- 

1 “ Un nouveau parasite de ble.” Societc de Biolog. a Toidome, 1S92. 


SEPTOSPORIUM. 


519 


spot on Vitis calif arnica in California. The leaves become 
quite black on the lower surface, brown on the upper. The 
fungus has not as yet been reported on cultivated vines. 

Fumago. 

Conidia grey and two- or three-celled. 

The species belong to Capnodium (see p. 181). 


3. FAM. STILBEAE. 

1. Ser. Hyalostilbeae. 

Sect. Amerospcrrae. 

Stysanus. 

Conidia pale-coloured, more or less spherical, and developed 
on a dark cylindrical or clavate erect stroma. 

Stysanus veronicae Pass. 1 This produces irregular spots on 
the leaves of cultivated Veronica longifolia in Italy, and causes 
the plant to wither. The columnar stromata are produced 011 
the lower surface of the leaves, and give off unicellular conidia. 

St. ulmariae M‘W. 2 On Spirea Ulmaria in Ireland. 

Isaria. 

Stroma erect, clavate, generally branched and bearing conidio- 
phores all over. The conidia are abjointed from the apex of 
the conidiophores, and are unicellular, hyaline, and rounded. 

Isaria fuciformis Berk. 3 This disease, first observed in 
Australia, is described by Smith as occurring in England. It 
attacks grasses, especially Festucci, during summer. The stems 
and ears are glued together by the fungus-stroma, and conidia 
are developed on all parts of the plants. 

2. Ser. Phaeostilbeae. 

Sect. Fhragmosporae. 

Isariopsis. 

Conidia pale-coloured, cylindrical, and pluricellular. 

Isariopsis griseola Sacc. 4 produces spots on leaves of living 

1 Hedwigia, 1877, p. 123. 

2 M‘Weeney, Irish Naturalist, 1895, p. 273. 

3 Worth. G. Smith, Diseases of Field and Garden Crops , London, 1884, p. 55. 

4 Briosi and Cavara, Funghi parasit. 


o-JO 


FUNGI IMPERFECTI. 


cultivated kidney bean. The mycelium lives in the leaf-tissues 
and forms stromata under the stomata, from which the conidio- 
phores arise in tufts. The fungus often occurs along with 

Uromyces phaseoli. 

Other species of Isariopsis are recorded on the living leaves 
of various host-plants, e.g. Cerastium and Stcllaria. 


4 . FAM. TUBERCULARIEAE. 

Volutella. 

The conidial patch or sporodochium is disciform, regular, 
and fringed, or studded over with elongated spine-like hyphae. 
Conidiophores simple or branched, and bearing elliptical or 
oblong conidia. 

The majority of the species of Volutella frequent only dead 
plant remains. Atkinson, 1 however, describes and figures a 
widespread carnation-disease in North America, which is ascribed 
to a species as yet unnamed. Fresh cuttings are most commonly 
attacked, and exhibit dirty brown depressed areas, which soon 
ruin the cutting for purposes of cultivation. 

Fusarium. 

Sporodochium more or less effused. Conidia spindle-shaped 
or sickle-like, pluricellular when mature. The conidiophores 
are branched, and give off the conidia from their apex. 

Fusarium heterosporium Nees. Frank 2 found a field of 
rye near Kiel completely destroyed, and the ears quite over- 
grown by this fungus. I have found it on ears of Lolium 
perenne and Molinia cocrulea in Bavaria. 

Species of Fusarium have been frequently described as causing 
injury to cereal and grass-crops, 3 in some cases to a serious 
extent. 

While most of the species of Fusarium are found only on 
dead or dying plant-remains, a parasitic mode of life has been 
ascribed to some. 

Fusarium lycopersici Sacc. 4 The “ Sleeping 1 hsease ” of 

*“ Carnation Diseases” in Report of American Carnation Society, 1893. 

2 Jahrhurh d. deutsch. /andwirfh. GeseJI . , 181)2. 

' Worth. G. Smith, Diseases of Crops, 1SS4, p. 208. 

Rostrup (Fusarium avetiaceum on Out) Landhoskrtfler, w, 181)8. 

■•Massee, Gardener's Chronicle, xvii., 1895, p. 707. (Kilit. ) 


FUSARIUM. 


521 


tomatoes. This tomato disease lias proved very destructive 
during recent years in Britain, particularly in the Isle of 
Wight and the Channel Islands. Plants are attacked when 
quite young, but the disease seldom manifests itself outwardly 
till the plant is full grown. The first symptom of disease 
is drooping of the leaves, with or without discoloration. At 
this stage the roots of attacked plants will be found to have a 
yellowish brown colour in the wood region. The mycelium 
of this fungus will be found in the vessels and other elements 
of the root. They are believed to originate from resting-spores 
which have hibernated in the soil and given off germ-tubes by 
which young rootlets were infected. The mycelium makes its 
way up the tomato stem, discolouring the vascular bundles as it 
goes. The conidia are produced on all diseased organs as a 
whitish bloom on the epidermis. The earlier conidia (Diplo- 
cladium) are oval and one- or two-celled, but they are soon 
replaced by pale orange crescent-shaped conidia of the true 
Fusarium type. The resting-spores are produced on the hyphae 
in the tissues of the decaying host-stein ; after hibernation, they 
germinate and produce hyphae which give off the Diploclctdium 
stage. Massee found that only the germ-tubes from resting- 
spores were able to infect tomato planta The same author 
does not consider fungicides of much avail on account of the 
disease beginning from the roots. Careful removal and destruc- 
tion of all infected material, and a liberal application of lime 
to the soil are measures recommended. 

Fus. limonis Briosi (Fusisporium limonis Briosi). This is 
given by Briosi as the cause of “ mal-di-gomma ” of orange 
and lemon trees in Italy and elsew r here ; 1 Webber and Swingle 2 
ascribe the disease of the orange and lemon in Florida known 
as “ foot-rot ” to the same fungus. In Florida the damage done 
is great and much more serious than that caused by any other 
disease of the same plants. It may be recognized by the 
exudation of gum from patches near the base of the tree. The 
patches enlarge and the disease spreads round the trunk and 
downwards into the roots, passing inwards from bark to cambium 
and wood, killing the tissues as it goes. Other symptoms 

’Briosi, “Mai di gomma,” Memoria della R. Acad, del Lincei, Rome, 1878. 

2 Webber and Swingle, “Diseases of citrous fruits in Florida.” U.S. America 
Dept, of Acjricxdture. Bulletin, No. 8, 1896. (Edit.) 


522 


FUNGI IMPERFECTI. 


are sparse foliage, small yellowish leaves, and death of the 
smaller branches over the tree. Sweet seedling orange ( Citrus 
aurantium ) and lemon ( C . limonum ) are most subject to this 
malady, the grape-fruit ( C . clecumana) is only slightly liable, 
and the sour orange (C. bigaraclia) is almost wholly exempt. 
For this reason sour orange stocks should be used on lowlands 
and ilatwoods, and grape-fruit stocks on the higher lands. The 
most effective treatment is to remove the soil around the crown 
roots by using a jet of water. Diseased hark should also be 
cut away and the wounds painted over with carbolic acid or 
sulphur wash. Good drainage to promote root aeration and 
the avoidance of excessive use of nitrogenous manures are also 
recommended. 

Fus. vasinfectum Atks. 1 A species found by Atkinson to 
cause a cotton-disease known as “ frenching.” This consists in 
a discoloration of the leaf from the margins inwards, at first 
pale or yellow, but turning to brown. A mycelium was found 
in the tissues of the stem, causing the vascular bundles to 
assume a light brown colour. The host-plants are either killed 
or so seriously affected that the crop is injured. The conidia 
formed are of the pleuriseptate slightly curved Fusarium type. 

Atkinson 2 in the course of his investigations on carnation 
diseases found a Fusarium present in all cases of the “ carnation 
rosette.” The stems remain short and stunted with their leaves 
small and crowded together. A mycelium was present in the 
tissues of the stem and caused discoloured spots. 


II. THE PATHOGENIC SLIME-FUNGI. 

MYXOMYCETES. 

The Myxomycetes’* rank amongst the lowest of plant-forms. 
They show so close relationship to the lowest animals that 
certain groups ( Monad ina ) receive greater consideration from 
the zoologist than from the botanist. They exhibit in their 

’Atkinson, “Cotton Diseases,” Alabama Agric. Exper. Station Bulletin , No. 
41, 1 Sfl‘2. (Edit.) 

2 “ Carnation Dineanex ” at American Carnation Society, 1803. 

3 The more important literature dealing with this family will be found in: 
I)e Bary, Morphology anil Biology of tin Fungi (English Edition); Lister, The 
Myrt/ozoa, London, 1805; Zopf in Schenk's Handbvch </»>• Botanik , ill., 1887 : 
Schroeter, “Myxomycetes” in Die natiirlieh. I'JIanzenfa milii n, I., ISO'-’. 


THE PATHOGENIC SLIME-FUNGI. 


523 


mode of reproduction a close resemblance to the Fungi, and as 
a result of their lack of chlorophyll, they share with Bac- 
teria and Fungi the peculiarities of saprophytic and parasitic 

nutrition. 

The vegetative body of the Slime-fungi consists of naked 
protoplasm without a firm membrane. Multiplication is effected 
chiefly by spherical spores with the same external appearance 
as the usual fungus-spore. Immediately on reaching maturity 
the spores germinate in water and burst, setting free a mass of 
plasma provided with a nucleus and vacuoles, and in which an 
outer movable hyaloplasma can be distinguished from an enclosed 
granular plasma. The hyaloplasma gives off delicate pseudopodia 
capable of extension and retraction, it may also take the form 
of a flagellum or of cilia. The organism is enabled by means 
of the pseudopodia to creep over firm objects as an “ amoeba ” ; 
by the cilia it can propel itself through water, as a “ swarmer ” 

or “ zoospore.” A zoospore in the course of its development 

generally loses its cilia and becomes an amoeba, and both 
forms can multiply by division. The amoebae creep together 
in large numbers, and either coalesce completely into masses, 

or remain simply in contact as aggregations. In this way 

plasmodia are formed, frequently of considerable size and of 
conspicuous colour. The plasmodia maintain a constant move- 
ment, both as a whole and in the form of internal streamings. 
Besting stages have been observed at each motile stage of 
the life-history ; thus swarm-spores rest as microcysts, young 
plasmodia as thick-walled cysts, and mature plasmodia as multi- 
cellular sclerotia. 

Multiplication of the Myxomycetes also takes place by spore- 
formation. In the Acrasieae and Phytomyxinae the spores are 
developed freely from the plasma. The Exosporeae, a very 
small division, have their spores developed on the outside 
of sporophores. In the greater number (Endosporeae) the 
spores are formed in special enclosures, which may be a spor- 
angium produced from a single plasmodium, or an aethalium — a 
cushion-like structure consisting of numerous imperfectly defined 
sporangia. The sporangia are often of considerable size, some- 
times not unlike the sporocarps of the Gasteromycetes, spherical 
or pear-shaped and stalked. Sporangia of this highly developed 
kind may even exhibit a certain differentiation into a wall or 


524 


THE PATHOGENIC SLIME-FUNGI. 


rind of compact plasma enclosing the spores, and frequently a 
supporting skeleton or capillitium is present consisting of 
numerous filaments of hardened plasma. 

Schroeter divides the Myxomycetes into three divisions, the 
Acrasieae, Phytomyxinae, and Myxogasteres (including the Exos- 
poreae and Eiulosporeae). Parasitic forms occur only in the 
second of these groups. If, however, all the forms included 
by Zopf in his group of Mycetozoa be taken into account 
many of them will be found to act as parasites and to cause 
frequent epidemics amongst algae and lower fungi. 

We shall here consider only the genera Plasmodiophora, 
Tetramyxa, and Sorosphaera. The genus Phytomyxa of Schroeter, 
containing those micro-organisms which cause the root-tubercles 
of Leguminosae, has already been considered in our general 
part (see p. 101). 


Plasmodiophora. 

Spores spherical and developed inside the host-cells. This 
genus causes diseases of considerable economic importance. 

Plasmodiophora brassicae Wor. 1 This species attacks all 
kinds of cabbage, kale, turnip, kohl rabi, and other varieties of 
Brassica Papa, B. Napus, B. oleracea, and other edible Cruciferae; 
also other plants from the same order, such as Ibcris umbel lata, 
Capsella bursa-pastor is, Matliiola incana, etc. 

The symptoms of the disease are manifold swelling, out- 
growth, and branching of the roots at all stages of growth, 
with a more or less marked stunting of the foliage, according 
to the season of attack (Fig. .‘115). The forms assumed by 
deformed roots are very variable and have gained the disease 
many designations. In Britain it is known as “ finger and 
toe disease,” “club-root,” “clubbing,” and “anbury”; in Bel- 
gium as “ maladie digitoire ” or “ Yingerziekte ” ; in Germany 
as “ Kropf ” or “ Kohlhernie.” 

The disease was first recorded in Scotland about ITS'.), but 
now it has a very wide distribution, appearing in all places 
where cabbage, turnips, and allied vegetables are cultivated on 
a large scale. The roots after swelling become rotten and 

O o 

1 Woronin, Prinyshviin * Jahrbuch, xi., 1S7S, p. 548. Eycleshymer ( Journal 
of Mycology, vii., p. 79) gives a good account of its distribution in America. 
Massce, Tranmction s of Itoi/nt Soriify of London, i.vn., 1895. 


PLASMODIOPHORA. 


525 


decay, so that not only is the root itself worthless, bnt the 
aerial shoot is badly developed. The destruction is greatly 
favoured by moist rainy years. 

The malformations of the root are the result of hypertrophy 
of the host-cells due to a stimulus exerted by the plasmodium 
of Plasmodiophora, not only on the contents of cells inhabited 
by it, but also extending into the cells of the whole neigh- 
bouring tissue. The cells so influenced enlarge in size and 



Fig. 315. — Plasmodiophora brassicae. Effects on Turnips grown in Scotland, 
(v. Tubeuf phot.) 


become divided up by new cell-walls. The plasmodium makes 
its way from cell to cell by means of the wall-pits, and 
by absorbing the contents it grows and tills the whole cell. 
On exhaustion of food, and without previous enclosure in a 
membrane, the plasmodium forms itself into spores, so that the 
tissues of attacked roots become completely tilled with thick- 
walled spores, which are set free only after decay of the 
surrounding tissues and cell-membranes. The spores hibernate, 
and in spring myxamoebae slip out, capable of infecting 



THE PATHOGENIC SLIME-FUNGI. 


526 

young roots of newly germinated cabbage, turnips, etc. They 
do this by penetrating the cell-wall, probably that of a hair 
to begin with, and the malformation ensues. The myxamoebae 
possess a flagellum and pseudopodia, so that they are fitted for 



Fio. 316 . — Platmodiophora 6)*aMicac. Effects on Turnip grown in Russia. 
(After Worouin.) 


different modes of locomotion. When entrance into a host-cell 
lias been effected, a plasmodium is formed and growth proceeds 
as just described. 

Wakker 1 describes, an enlargement of the attacked cells 
and an irregular growth of the roots, associated with a rudi- 

1 Priiu/sheim's Jahrbuch, 1892. 


PI.ASMODIOPHORA. 


527 


mentary condition and twisted course of the vessels, and an 
accumulation of transitory starch in the tissues. 

[The methods at our disposal for combating this parasite all 
work indirectly. Its spores seem to retain their vitality for two, 
three, or more years, hence one very evident measure is not to 
plant the same crop in succession on land which has been attacked. 
As, however, all Cruciferae are liable to injury from this source. 


Fig. 317. — Plasmodiophora brassicae on Turnip. (After Woronin.) 



neither would it be advisable to let say, turnips follow 
cabbage or kohl rabi on infected land. For the same reason 
weeds belonging to the order Cruciferae should not be allowed 
to obtain a footing near land where plants liable to “ finger and 
toe ” are under cultivation. In Scotland, where turnips are 
necessary in all crop-rotations, a four-year rotation does not 
give complete exemption from this disease, nor is five years 


528 


THE PATHOGENIC SLIME-FUNGI. 


considered quite a safe interval, but seven years is, and with 
good management the disease, though by no means uncommon, 
only then attains serious dimensions in moist seasons. Massee 
points out that the development of the fungus is favoured by 
acids and checked by alkalis ; this explains the well-known 
beneficial effects of dressings of lime or potash in keeping the 
disease in check. With a six or seven-year rotation, and the 
application of lime once in the rotation, the disease should 



Fig. :<18. Hypertrophied cells from a Cabbage-root attacked by Platmiodiophoru 
brassicfu . {Several of the cells are filled with spores, (v. Tubeuf del.) 


never be very injurious. The direct application of farmyard 
manure to the turnip crop should also lie avoided, especially 
if the stock which made the manure was fed on diseased turnips; 
this is necessary because it has been found that the spores are 
not killed when eaten by animals.] (Edit.) 

Plasmodiophora vitis Yiala et Sauv . 1 This is said to 
cause a Vine disease known as “ Brunissure,” which within 
recent years has caused considerable loss in France, North 
America, and Southern Russia . 2 The early symptoms are light- 
brown star-shaped spots on the upper surface of the leaves 
between the ribs. The spots enlarge and cause a premature fall 
of the leaf, whereby the grapes are prevented from maturing. 

1 Viala et Sauvageau, Coin/ii. rend., cxiw, 1892. 

2 Cooke (Gardener's Chronicle, 1893) refers swellings found by him on roots of 
the vine in England to the action of this fungus. (Edit.) 


PLASMODIOPHORA. 


529 


The above-named investigators found plasmodia in various stages 
of development in the palisade cells, and later in the spongy 
parenchyma of diseased leaves. On treatment with “ eau de 
javelle ” the plasmodia remained visible, whereas the contents 
of healthy cells disappeared. Spore-formation has not as yet 
been observed. The same parasite has been seen in vines in 
the Rhine district. 

Recently Debray and Brive 1 have, in consequence of their 
researches on Brunissure, removed the fungus from the genus 
Plasmodiophora, and founded for it a new group Pseudocow, mis, 
with a position near Vampyrella and Myxomycetes. This same 
fungus they also found in a large number of plants from thirty 
different natural orders. 

Plasmodiophora californica Yiala et Sauv . 2 is another vine 
parasite which causes greater damage than the preceding species. 
Reddish leaf-spots are produced, and extend so rapidly that the 
leaves may drop early in spring. The parasite also affects the 
shoots to such a degree that an abnormal number of shortened 
branches are developed, the wood of which exhibits brown 
stripes in autumn. 

It has not as yet been quite proved that the plasma observed 
in withered vine leaves really consists of plasmodia of the 
above two species of Plasmodiophora, nor have spores been 
found. The true cause of the diseases has probably still to be 
explained. 

In cases of root-deformation in pear, Mtiller-Thurgau 3 observed 
a slime-fungus in cells of the root-parenchyma. 

Tetramyxa. 

Spores united four together as tetrads and enclosed in a 
delicate membrane. 

Tetramyxa parasitica Cfoeb . 4 First found by Goebel in 
ditches of marshy meadows, causing tuberous balls of a whitish- 
green to browm colour on leaves, flowers, and stalks of Puppia 
rostellata. Sections of the swellings showed the parenchyma 
to be divisible into a dark brown central part consisting of 

1 Compt. rendu., cxx., 1895;